# HIFreeTools

> Free, fast online tools — calculators, unit converters, text and developer utilities, finance and health calculators, and random generators. Most tools run entirely in your browser with no sign-up and nothing uploaded. Results are general information only and are not professional (financial, medical, legal, or tax) advice.

Site: https://hifreetools.com
Operator: HIFreeTools, an independent project by a solo developer based in South Korea.

## Calculators
- [Basic Calculator](https://hifreetools.com/calculators/basic-calculator): A free online calculator for everyday math — add, subtract, multiply, divide, and use parentheses with correct order of operations. In your browser.
- [Basic Probability Calculator](https://hifreetools.com/calculators/probability-calculator): Calculate basic probability, complement, union, and intersection of events instantly. Free probability calculator with formulas, examples, and step-by-step results.
- [Circle Calculator](https://hifreetools.com/calculators/circle-calculator): Free circle calculator: enter radius, diameter, circumference, or area and instantly get the other three using C = 2πr and A = πr². Fast and accurate.
- [Concrete Calculator](https://hifreetools.com/calculators/concrete-calculator): Calculate concrete volume for a slab, footing or column in cubic yards, cubic feet and cubic metres, plus the number of 40, 60 or 80 lb bags. Free.
- [Confidence Interval Calculator](https://hifreetools.com/calculators/confidence-interval-calculator): Free confidence interval calculator for a population mean. Enter sample mean, standard deviation, and size to get the margin of error and 90%, 95%, or 99% CI.
- [Correlation Coefficient Calculator](https://hifreetools.com/calculators/correlation-coefficient-calculator): Free Pearson correlation coefficient calculator. Paste two equal-length data lists to get r (−1 to 1), the sample size n, and a plain-English strength interpretation.
- [Decimal to Fraction Calculator](https://hifreetools.com/calculators/decimal-to-fraction-calculator): Convert any terminating decimal to a simplified fraction and mixed number. See every GCD reduction step. Free, instant, works in your browser.
- [Distance Between Two Points Calculator](https://hifreetools.com/calculators/distance-between-points-calculator): Find the distance and midpoint between two points (x1,y1) and (x2,y2) instantly. Uses the distance formula d=√((x2−x1)²+(y2−y1)²) with worked steps.
- [Expected Value Calculator](https://hifreetools.com/calculators/expected-value-calculator): Calculate expected value (EV) instantly. Enter outcomes and probabilities to find the weighted average result. Free browser-based expected value calculator.
- [Exponent Calculator](https://hifreetools.com/calculators/exponent-calculator): Raise any base to any power, including negative and fractional exponents. Get instant results like 2^10 = 1024 and 27^(1/3) = 3. Free, in your browser.
- [Factorial Calculator](https://hifreetools.com/calculators/factorial-calculator): Calculate the factorial n! of any non-negative integer instantly and exactly. Uses BigInt for huge results like 100!, with scientific form and digit count.
- [Final Grade Calculator](https://hifreetools.com/calculators/final-grade-calculator): Find the exact score you need on your final exam to hit your target course grade, from your current grade and the final's weight. Free and instant.
- [Fraction Calculator](https://hifreetools.com/calculators/fraction-calculator): Free fraction calculator that adds, subtracts, multiplies and divides two fractions. Get a fully reduced fraction, decimal and mixed number.
- [Fuel Efficiency Calculator](https://hifreetools.com/calculators/fuel-efficiency-calculator): Calculate fuel efficiency in MPG or L/100km instantly. Enter distance and fuel used to find your car's economy, plus cost-per-mile and unit conversion.
- [GPA Calculator](https://hifreetools.com/calculators/gpa-calculator): Calculate your GPA on the standard US 4.0 scale. Enter each course's letter grade and credit hours for an instant, accurate credit-weighted grade point average.
- [Grade Percentage Calculator](https://hifreetools.com/calculators/grade-percentage-calculator): Calculate your grade as a percentage instantly. Enter points earned and total points to find your score, letter grade, and GPA equivalent in one click.
- [LCM & GCD Calculator](https://hifreetools.com/calculators/lcm-gcd-calculator): Free LCM and GCD calculator. Find the greatest common divisor (GCF) and least common multiple of any list of integers instantly, with the worked steps shown.
- [Logarithm Calculator](https://hifreetools.com/calculators/logarithm-calculator): Free logarithm calculator: find logₐ(x) for any base using ln(x)/ln(b), plus the natural log and common log of x. Instant, accurate, with worked examples.
- [Margin of Error Calculator](https://hifreetools.com/calculators/margin-of-error-calculator): Free margin of error calculator: enter confidence level, sample size, and proportion to get the survey MoE instantly. Uses MoE = Z·√(p(1−p)/n).
- [Matrix Calculator](https://hifreetools.com/calculators/matrix-calculator): Add, subtract and multiply matrices and find the determinant, inverse and transpose — up to 5×5, computed instantly in your browser. Free, no sign-up.
- [Mean Median Mode Calculator](https://hifreetools.com/calculators/mean-median-mode-calculator): Paste a list of numbers to instantly get the mean, median, mode, range, variance, and standard deviation. Free, accurate, and works right in your browser.
- [Midpoint Calculator](https://hifreetools.com/calculators/midpoint-calculator): Free midpoint calculator finds the midpoint of two points (x1,y1) and (x2,y2) using the midpoint formula. Shows each step, supports negatives and decimals.
- [Modulo Calculator](https://hifreetools.com/calculators/modulo-calculator): Compute a mod b — the remainder of a divided by b — plus the quotient and the always-positive Euclidean modulo. Free and instant in your browser.
- [P-value Calculator](https://hifreetools.com/calculators/p-value-calculator): Find the p-value from a z, t, chi-square or F test statistic — one- or two-tailed. Accurate to ~6 significant figures, instant, in your browser.
- [Paint Calculator](https://hifreetools.com/calculators/paint-calculator): Work out how many gallons (or litres) of paint you need from wall area or room size, coats, coverage, and doors/windows. Free and instant.
- [Percent Error Calculator](https://hifreetools.com/calculators/percent-error-calculator): Calculate percent error from a measured value and the true value. Shows the absolute error too. Free and instant, runs in your browser.
- [Percentage Change Calculator](https://hifreetools.com/calculators/percentage-change-calculator): Calculate the percentage increase or decrease between two numbers. Enter the old and new value to get the percent change instantly, in your browser.
- [Percentage Increase/Decrease Calculator](https://hifreetools.com/calculators/percentage-increase-decrease-calculator): Increase or decrease any number by a percentage. Enter a starting value and a percent to get the new value and the exact amount of change instantly.
- [Percentile Calculator](https://hifreetools.com/calculators/percentile-calculator): Free percentile calculator. Paste your numbers, pick a percentile (0–100), and instantly get the value using linear interpolation — with the math shown.
- [Perimeter Calculator](https://hifreetools.com/calculators/perimeter-calculator): Free perimeter calculator for a square, rectangle, triangle, circle, or parallelogram. Pick a shape, enter the sides, and get the perimeter with the formula shown.
- [Permutation and Combination Calculator](https://hifreetools.com/calculators/permutation-combination-calculator): Free permutation and combination calculator. Instantly compute nPr, nCr, n! and r! for any integers n ≥ r ≥ 0, with the formulas and worked steps shown.
- [Prime Number Checker](https://hifreetools.com/calculators/prime-number-checker): Free prime number checker: instantly tells if a number is prime or composite, shows its prime factorization (e.g. 84 = 2² × 3 × 7) and smallest factor.
- [Proportion Calculator](https://hifreetools.com/calculators/proportion-calculator): Solve a proportion a/b = c/d for any missing value by cross-multiplication. Leave one box blank and get the answer instantly, in your browser.
- [Pythagorean Theorem Calculator](https://hifreetools.com/calculators/pythagorean-theorem-calculator): Solve any right triangle: enter any two of legs a, b and hypotenuse c to find the third side, plus area and perimeter. Free, instant, and shows the formula.
- [Quadratic Formula Calculator](https://hifreetools.com/calculators/quadratic-formula-calculator): Solve any quadratic equation ax²+bx+c=0 instantly. Get the real or complex roots, the discriminant, and the vertex — with the formula and every step shown.
- [Ratio Calculator](https://hifreetools.com/calculators/ratio-calculator): Simplify any ratio to its lowest terms and solve equivalent ratios (A:B = C:?). See the decimal and percentage too. Free, instant, in your browser.
- [Roman Numeral Converter](https://hifreetools.com/calculators/roman-numeral-converter): Free Roman numeral converter. Turn any number from 1 to 3999 into Roman numerals and decode Roman numerals back to integers instantly, with validation.
- [Rounding Calculator](https://hifreetools.com/calculators/rounding-calculator): Round a number to decimal places or to the nearest 10, 100, or 1000, with round, floor, or ceiling modes. Free and instant in your browser.
- [Sample Size Calculator](https://hifreetools.com/calculators/sample-size-calculator): Free sample size calculator for surveys. Enter confidence level, margin of error and expected proportion to find how many people you need, with finite-population correction.
- [Scientific Notation Calculator](https://hifreetools.com/calculators/scientific-notation-calculator): Convert numbers to and from scientific notation and E-notation, plus standard decimal form. Enter 0.00045 or 6.02e23 — instant, in your browser.
- [Significant Figures Calculator](https://hifreetools.com/calculators/significant-figures-calculator): Count the significant figures in any number and round to a chosen number of sig figs. Handles leading and trailing zeros correctly. Free, instant, in your browser.
- [Slope Calculator](https://hifreetools.com/calculators/slope-calculator): Free slope calculator: enter two points (x1, y1) and (x2, y2) to get the slope m, y-intercept b, the line equation y = mx + b, and the angle in degrees.
- [Square Footage Calculator](https://hifreetools.com/calculators/square-footage-calculator): Calculate square footage for rectangles, circles, triangles and more in feet, metres, inches or yards — with cost and multi-room totals. Free, instant.
- [Square Root Calculator](https://hifreetools.com/calculators/square-root-calculator): Find the square root of any number, plus cube roots and custom nth roots. Flags perfect squares and powers. Free, instant, in your browser.
- [Standard Deviation Calculator](https://hifreetools.com/calculators/standard-deviation-calculator): Free standard deviation calculator. Paste your numbers to get mean, variance, and both population (÷n) and sample (÷n−1) standard deviation, with steps shown.
- [Triangle Area Calculator](https://hifreetools.com/calculators/triangle-area-calculator): Free triangle area calculator. Find area instantly from base and height (A=½·b·h) or from three sides using Heron's formula, with triangle-inequality validation.
- [Trigonometry Calculator](https://hifreetools.com/calculators/trigonometry-calculator): Evaluate sin, cos, tan and their inverses in degrees or radians, and solve a right triangle from any two values. Free, instant, in your browser.
- [Variance and Standard Deviation Calculator](https://hifreetools.com/calculators/variance-calculator): Calculate population or sample variance and standard deviation instantly. Enter comma-separated numbers for mean, variance, std dev, and step-by-step results.
- [Volume, Area & Depth Calculator](https://hifreetools.com/calculators/volume-area-depth): Relate volume (m³) and area (m²) using a depth: Area = Volume ÷ Depth. Enter any two of volume, area, or thickness. Free, in your browser.
- [Weighted Average Calculator](https://hifreetools.com/calculators/weighted-average-calculator): Calculate a weighted average (weighted mean) from values and their weights. Add as many rows as you need. Free and instant in your browser.
- [Wolfram MathWorld — Arithmetic Mean](https://hifreetools.com/calculators/average-calculator): Calculate the mean, median, mode, range, sum, and count of any list of numbers. Free, instant, with the formulas shown. Paste your numbers and go.
- [Wolfram MathWorld — Percent](https://hifreetools.com/calculators/percentage-calculator): Calculate a percentage of a number, what percent one value is of another, and percentage increase or decrease. Free, instant, with the formula shown.
- [Z-Score Calculator](https://hifreetools.com/calculators/z-score-calculator): Free z-score calculator. Enter a raw value, the population mean, and the standard deviation to get the standard score z = (x − μ) / σ to 4 decimals, instantly.

## Unit Converters
- [Acres to Square Feet Converter](https://hifreetools.com/converters/acres-to-square-feet): Convert acres to square feet instantly. 1 acre = 43,560 sq ft. Essential for real estate, land surveys, and property dimensions.
- [Bar to PSI Converter](https://hifreetools.com/converters/bar-to-psi): Convert bar to PSI instantly. 1 bar = 14.5038 psi. Handy for tyre and tube pressures, diving, and equipment rated in bar.
- [Calories (kcal) to Kilojoules Converter](https://hifreetools.com/converters/calories-to-kilojoules): Convert calories (kcal) to kilojoules instantly. 1 kcal = 4.184 kJ. Useful for comparing US/UK calorie figures with kilojoule nutrition labels.
- [Celsius to Kelvin Converter](https://hifreetools.com/converters/celsius-to-kelvin): Convert Celsius to Kelvin easily. Add 273.15 to your Celsius value. Essential for science, chemistry, and thermodynamics.
- [Cubic Meters to Liters Converter](https://hifreetools.com/converters/cubic-meters-to-liters): Convert cubic meters to liters instantly. 1 m³ = 1,000 L. Useful for water tanks, construction volumes, and capacity.
- [Cups (US) to Milliliters Converter](https://hifreetools.com/converters/cups-to-ml): Convert US cups to mL for any recipe. 1 US cup = 236.6 mL. Essential for adapting American recipes to metric measuring equipment.
- [Currency Converter](https://hifreetools.com/converters/currency-converter): Convert between 160+ world currencies with live exchange rates. Swap any pair, save conversions to compare, and copy the result. Free, no sign-up.
- [Fahrenheit to Celsius Converter](https://hifreetools.com/converters/fahrenheit-to-celsius): Convert Fahrenheit to Celsius instantly. Formula: multiply by 5/9 and subtract 32. Perfect for weather, cooking, and fever readings.
- [Fahrenheit to Kelvin Converter](https://hifreetools.com/converters/fahrenheit-to-kelvin): Convert Fahrenheit to Kelvin. Use the formula: (°F − 32) × 5/9 + 273.15. For bridging US readings and scientific work.
- [Feet to Inches Converter](https://hifreetools.com/converters/feet-to-inches): Convert feet to inches. 1 ft = 12 in. Perfect for expressing heights, lumber and construction, and furniture measurements.
- [Feet to Meters Converter](https://hifreetools.com/converters/feet-to-meters): Convert feet to meters instantly. 1 ft = 0.3048 m exactly. Perfect for heights, building dimensions, and US-to-metric conversions.
- [Fluid Ounces (US) to Milliliters Converter](https://hifreetools.com/converters/fluid-ounces-to-ml): Convert US fluid ounces to milliliters. 1 fl oz = 29.57 mL. Perfect for bottled drinks, perfume, cosmetics, and recipes.
- [Gallons (US) to Liters Converter](https://hifreetools.com/converters/gallons-to-liters): Convert US gallons to liters instantly. 1 gallon = 3.785 liters. Perfect for fuel tanks, aquariums, and water usage calculations.
- [Grams to Ounces Converter](https://hifreetools.com/converters/grams-to-ounces): Convert grams to ounces (and back) instantly using 1 oz = 28.349523125 g, with a kitchen-friendly table. Free, accurate, in your browser.
- [Grams to Pounds Converter](https://hifreetools.com/converters/grams-to-pounds): Convert grams to pounds for food, packages, and product specifications. Factor: 0.0022046 per gram.
- [Hectares to Acres Converter](https://hifreetools.com/converters/hectares-to-acres): Convert hectares to acres instantly. 1 hectare = 2.471 acres. Perfect for agricultural land, parks, and international property transactions.
- [Inches to Centimeters Converter](https://hifreetools.com/converters/inches-to-cm): Convert inches to centimeters. 1 inch = 2.54 cm exactly. Ideal for screen sizes, clothing measurements, and DIY projects.
- [Kelvin to Celsius Converter](https://hifreetools.com/converters/kelvin-to-celsius): Convert Kelvin to Celsius by subtracting 273.15. Quick converter for physics, astronomy, and scientific research.
- [Kilograms to Grams Converter](https://hifreetools.com/converters/kg-to-grams): Convert kilograms to grams using the factor 1000. Essential for recipes, labs, and precise measurements.
- [Kilograms to Stones Converter](https://hifreetools.com/converters/kg-to-stones): Convert kilograms to stones and pounds. Essential for UK and Ireland body weight tracking and health discussions.
- [Kilojoules to Calories (kcal) Converter](https://hifreetools.com/converters/kilojoules-to-calories): Convert kilojoules to calories (kcal) instantly. 1 kcal = 4.184 kJ. Ideal for reading nutrition labels that show food energy in kilojoules.
- [Kilometers per hour to Miles per hour Converter](https://hifreetools.com/converters/kmh-to-mph): Convert kilometers per hour to miles per hour instantly. 1 km/h = 0.621 mph. Perfect for car speedometers and road trip planning.
- [Kilometers to Miles Converter](https://hifreetools.com/converters/km-to-miles): Convert kilometers to miles. 1 km = 0.6214 miles. Perfect for running, cycling, marathons, road trips, and car odometers.
- [Kilopascals to PSI Converter](https://hifreetools.com/converters/kpa-to-psi): Convert kilopascals (kPa) to PSI instantly. 1 kPa = 0.145038 psi. Useful for tyre pressure, weather, and engineering specs.
- [Knots to Miles per hour Converter](https://hifreetools.com/converters/knots-to-mph): Convert knots to miles per hour fast. 1 knot = 1.151 mph. Use for boating, sailing, aviation, and hurricane tracking.
- [Liters to Gallons Converter](https://hifreetools.com/converters/liters-to-gallons): Convert liters to US gallons (and back) instantly using 1 US gallon = 3.785411784 L, with a table. Free and accurate. Note: US, not imperial, gallons.
- [Megapascals to PSI Converter](https://hifreetools.com/converters/mpa-to-psi): Convert megapascals (MPa) to PSI instantly. 1 MPa = 145.038 psi. Useful for material strength, hydraulics, and equipment ratings.
- [Meters per second to Kilometers per hour Converter](https://hifreetools.com/converters/ms-to-kmh): Convert meters per second to kilometers per hour instantly. 1 m/s = 3.6 km/h. Essential for physics, wind speed, and sports analytics.
- [Meters to Feet Converter](https://hifreetools.com/converters/meters-to-feet): Convert meters to feet (and back) instantly using 1 m = 3.280839895 ft, with a common-values table. Free, accurate, runs in your browser.
- [Meters to Yards Converter](https://hifreetools.com/converters/meters-to-yards): Convert meters to yards. 1 m = 1.0936 yd. Perfect for swimming pools, athletics tracks, and US sports conversions.
- [Miles per hour to Meters per second Converter](https://hifreetools.com/converters/mph-to-ms): Convert miles per hour to meters per second fast. 1 mph = 0.447 m/s. Perfect for physics homework and SI unit conversions.
- [Miles to Feet Converter](https://hifreetools.com/converters/miles-to-feet): Convert miles to feet. 1 mile = 5,280 feet. Use for walking distance, elevation gain, aviation altitudes, and track laps.
- [Miles to Kilometers Converter](https://hifreetools.com/converters/miles-to-km): Convert miles to kilometers (and back) instantly using 1 mile = 1.609344 km, with a table for common distances. Free and accurate.
- [Milliliters to Cups (US) Converter](https://hifreetools.com/converters/ml-to-cups): Convert milliliters to US cups instantly. 1 cup = 236.6 mL. Perfect for scaling metric recipes to US kitchen measurements.
- [MM to Inches Converter](https://hifreetools.com/converters/mm-to-inches): Convert millimeters to inches (and back) instantly using 1 inch = 25.4 mm, with a common-values table. Free, exact, runs in your browser.
- [MPH to KM/H Converter](https://hifreetools.com/converters/mph-to-kmh): Convert miles per hour to kilometers per hour (and back) instantly using 1 mph = 1.609344 km/h, with a speed table. Free and accurate.
- [Nautical Miles to Kilometers Converter](https://hifreetools.com/converters/nautical-miles-to-km): Convert nautical miles to kilometers. 1 nmi = 1.852 km. Essential for marine and air navigation, sea distances, and maritime speed.
- [NIST — SI units](https://hifreetools.com/converters/kg-to-lbs): Convert kilograms to pounds (and back) instantly, with the exact factor and a common-values table. Free, accurate, runs in your browser.
- [NIST — SI units](https://hifreetools.com/converters/cm-to-inches): Convert centimeters to inches (and back) instantly using the exact factor 1 inch = 2.54 cm, with a common-values table. Free, in-browser, accurate.
- [NIST — SI units](https://hifreetools.com/converters/celsius-to-fahrenheit): Convert Celsius to Fahrenheit (and back) instantly with the exact formula °F = °C × 9/5 + 32 and a reference table. Free and accurate.
- [Ounces to Grams Converter](https://hifreetools.com/converters/ounces-to-grams): Convert ounces to grams instantly with factor 28.3495. Perfect for cooking, baking recipes, and food labels.
- [Pints (US) to Liters Converter](https://hifreetools.com/converters/pints-to-liters): Convert US pints to liters. 1 US pint = 0.473 liters. Perfect for beer servings, dairy packaging, and US recipe quantities.
- [Pounds to Kilograms Converter](https://hifreetools.com/converters/lbs-to-kg): Convert pounds to kilograms using the exact factor 0.4536. Common for body weight, gym equipment, and luggage.
- [PSI to Bar Converter](https://hifreetools.com/converters/psi-to-bar): Convert PSI to bar instantly. 1 psi = 0.0689476 bar (1 bar = 14.5038 psi). Ideal for tyre pressure, compressors, and hydraulics.
- [Quarts (US) to Liters Converter](https://hifreetools.com/converters/quarts-to-liters): Convert US quarts to liters. 1 quart = 0.946 liters. Essential for stockpots, milk, oil changes, and large recipe quantities.
- [Square Feet to Square Meters Converter](https://hifreetools.com/converters/square-feet-to-square-meters): Convert square feet to square meters instantly. 1 sq ft = 0.0929 m². Essential for real estate, renovations, and interior design.
- [Square Kilometers to Square Miles Converter](https://hifreetools.com/converters/square-km-to-square-miles): Convert square kilometers to square miles instantly. 1 km² = 0.386 mi². Perfect for geographic areas, maps, and regional comparisons.
- [Square Meters to Square Feet Converter](https://hifreetools.com/converters/square-meters-to-square-feet): Convert square meters to square feet (and back) using 1 m² = 10.763910417 ft², with a table for room and floor areas. Free and accurate.
- [Stones to Kilograms Converter](https://hifreetools.com/converters/stones-to-kg): Convert stones to kilograms (and back) using 1 stone = 6.35029318 kg, with a body-weight table. Free and accurate. 1 stone = 14 pounds.
- [Tablespoons (US) to Milliliters Converter](https://hifreetools.com/converters/tablespoons-to-ml): Convert US tablespoons to milliliters. 1 tbsp = 14.79 mL. Ideal for precise sauces, oils, and small recipe quantities.
- [Teaspoons (US) to Milliliters Converter](https://hifreetools.com/converters/teaspoons-to-ml): Convert US teaspoons to mL instantly. 1 tsp = 4.93 mL. Essential for spice measurements, extracts, and liquid medicine dosing.
- [Yards to Meters Converter](https://hifreetools.com/converters/yards-to-meters): Convert yards to meters. 1 yard = 0.9144 m. Ideal for American football fields, textiles, and track-and-field events.

## Text Tools
- [Add Prefix and Suffix to Each Line](https://hifreetools.com/text/add-prefix-suffix-lines): Add a prefix and/or suffix to every line of text, with optional running line numbers and skip-empty-lines. Free, fast, and 100% private in your browser.
- [Bionic Reading Converter](https://hifreetools.com/text/bionic-reading): Convert any text into bionic reading format that bolds the first part of each word to guide your eyes. Adjustable intensity, copy as rich text, 100% in-browser.
- [Caesar Cipher Encoder/Decoder](https://hifreetools.com/text/caesar-cipher): Encode or decode text with the Caesar shift cipher online. Pick any shift 0-25, use the ROT13 preset, keep letter case, and copy the result. Free and private.
- [Citation Generator](https://hifreetools.com/text/citation-generator): Generate accurate APA, MLA, and Chicago citations for books and websites. Enter the author, title, year, publisher, and URL, then copy the formatted reference.
- [Diff Checker Text Compare](https://hifreetools.com/text/diff-checker): Compare two blocks of text line by line and highlight added, removed, and unchanged lines. Free, private, and runs entirely in your browser.
- [Fancy Text Generator](https://hifreetools.com/text/fancy-text-generator): Turn plain text into bold, italic, script, monospace, double-struck, circled, small caps and full-width Unicode styles for Instagram, TikTok and Discord bios.
- [Find and Replace Text](https://hifreetools.com/text/find-and-replace-text): Find and replace text online with case-insensitive, whole-word, and regex options, plus a live replacement count. Free and private — your text stays in your browser.
- [Invisible Character Generator](https://hifreetools.com/text/invisible-character): Copy invisible and zero-width Unicode characters for blank usernames, empty messages, and spacing. Pick U+200B, U+3164 Hangul Filler, U+2800 Braille blank, a.
- [Line Counter](https://hifreetools.com/text/line-counter): Free online line counter. Paste any text to count total lines, non-empty lines, unique lines, and duplicate lines instantly in your browser. Private, no upload.
- [Lorem Ipsum Generator](https://hifreetools.com/text/lorem-ipsum-generator): Generate Lorem Ipsum placeholder text by paragraphs, sentences, or words, and copy it instantly. Free, classic dummy text for mockups and layouts.
- [Morse Code Translator](https://hifreetools.com/text/morse-code-translator): Translate text to Morse code and Morse code back to text with the International standard map, plus audio beeps. Free and private — everything runs in your br.
- [Online Notepad](https://hifreetools.com/text/online-notepad): A distraction-free online notepad that autosaves to your browser so notes survive a reload. Live word and character count, plus download .txt, copy, and clea.
- [Reading Time Estimator](https://hifreetools.com/text/reading-time-estimator): Estimate how long it takes to read any text. Enter word count and reading speed to get minutes and seconds. Free, instant, browser-based tool.
- [Remove Duplicate Lines](https://hifreetools.com/text/remove-duplicate-lines): Remove duplicate lines from a list or text, with options to ignore case and trim spaces. Free and private — runs entirely in your browser.
- [Remove Empty Lines](https://hifreetools.com/text/remove-empty-lines): Delete blank and whitespace-only lines from text or a list, with options to trim each line or collapse blanks to one. Free, private, runs in your browser.
- [Remove Extra Spaces](https://hifreetools.com/text/remove-extra-spaces): Clean text by collapsing multiple spaces, trimming each line, and optionally removing blank lines. Instant and 100% in your browser — nothing uploaded.
- [Remove Line Breaks](https://hifreetools.com/text/remove-line-breaks): Free online tool to remove line breaks from text. Replace newlines with a space, nothing, or a custom separator, collapse extra spaces, and keep paragraphs.
- [Sort Lines Alphabetically](https://hifreetools.com/text/sort-lines): Sort text lines alphabetically A-Z or Z-A with options for case-insensitive sorting, numeric sort, duplicate removal, and reverse order. Works in your browser.
- [Text Case Converter](https://hifreetools.com/text/text-case-converter): Convert text between UPPERCASE, lowercase, Title Case, and Sentence case instantly. Free and private — your text never leaves your browser.
- [Text Reverser](https://hifreetools.com/text/reverse-text): Free online text reverser. Flip text backward by characters, words, or lines instantly in your browser. Emoji-safe, private, and 100% client-side.
- [Text to Slug Converter](https://hifreetools.com/text/text-to-slug): Convert text to clean URL-safe slugs instantly. Removes punctuation, strips accents, lowercases, and replaces spaces with hyphens. Works offline.
- [The Unicode Consortium](https://hifreetools.com/text/character-counter): Count characters with and without spaces, plus words and lines, against limits for tweets, meta tags, and bios. Free and private — text stays in your browser.
- [Word Counter](https://hifreetools.com/text/word-counter): Count words, characters, sentences, and paragraphs, plus estimated reading and speaking time. Free and private — your text never leaves your browser.
- [Word Frequency Counter](https://hifreetools.com/text/word-frequency-counter): Count how often each word appears in your text and get a ranked frequency table with counts and percentages. Optional stop-word removal. Runs in your browser.

## Developer Tools
- [ASCII Table](https://hifreetools.com/developer/ascii-table): Full ASCII table for codes 0–127 with decimal, hex, octal, binary, the character, and a description. Search by code or character. Free, in-browser.
- [Aspect Ratio Calculator](https://hifreetools.com/developer/aspect-ratio-calculator): Calculate the aspect ratio of any image or screen, scale dimensions while preserving ratio, and convert between common formats instantly in your browser.
- [Barcode Generator](https://hifreetools.com/developer/barcode-generator): Generate 1D barcodes (Code 128, EAN-13, UPC, Code 39 and more) and download as PNG or SVG. Free, instant, in your browser — no upload.
- [Base64 Encoder & Decoder](https://hifreetools.com/developer/base64-encoder): Encode text to Base64 and decode Base64 back to text, instantly and privately in your browser. Supports full Unicode (UTF-8). Free, no uploads.
- [Binary to Decimal Converter](https://hifreetools.com/developer/binary-decimal-converter): Convert binary numbers to decimal (and back) instantly. Shows step-by-step positional math, supports unsigned integers. Free, browser-based, no signup.
- [Bit and Byte Converter](https://hifreetools.com/developer/bit-byte-converter): Convert bits, bytes, kilobytes, megabytes, gigabytes, terabytes, and more instantly. Free, in-browser data storage unit converter. No sign-up needed.
- [Chmod Calculator](https://hifreetools.com/developer/chmod-calculator): Free chmod calculator. Tick read, write and execute for owner, group and other to get the octal value (755) and symbolic string (rwxr-xr-x) plus the chmod command.
- [Code to Image](https://hifreetools.com/developer/code-to-image): Turn a code snippet into a beautiful shareable image with window chrome, themes and syntax colors. Download PNG or copy, free, in your browser.
- [Credit Card Number Validator (Luhn)](https://hifreetools.com/developer/credit-card-validator): Check a card number with the Luhn algorithm and detect the brand (Visa, Mastercard, Amex, Discover). Runs in your browser — nothing is stored or sent. Free.
- [Cron Expression Generator](https://hifreetools.com/developer/cron-expression-generator): Build a 5-field cron expression from simple inputs, use common presets, and get a plain-English explanation of the schedule. Free, in-browser, no signup.
- [CSS Border Radius Generator](https://hifreetools.com/developer/border-radius-generator): Generate CSS border-radius with per-corner control in px or %, a live preview box, and copyable shorthand. Free, private, runs entirely in your browser.
- [CSS Box Shadow Generator](https://hifreetools.com/developer/box-shadow-generator): Visually build CSS box-shadow with live preview. Adjust offset, blur, spread, color, opacity, and inset, then copy the rgba() code. Free, runs in your browser.
- [CSS Gradient Generator](https://hifreetools.com/developer/css-gradient-generator): Build linear and radial CSS gradients visually. Set the angle, add color stops, see a live preview, and copy ready-to-use background CSS instantly.
- [CSV to JSON Converter](https://hifreetools.com/developer/csv-to-json): Convert CSV or TSV to a JSON array of objects, or turn JSON back into CSV. Handles quoted fields, custom delimiters, and headers. Free, runs in your browser.
- [Cubic Bezier Generator](https://hifreetools.com/developer/cubic-bezier-generator): Build CSS cubic-bezier() easing curves visually. Drag four control values, see the curve and a live animation, and copy the timing function instantly.
- [Denso Wave — QR Code (inventor)](https://hifreetools.com/developer/qr-code-generator): Create a QR code for a URL or text and download it as a PNG, right in your browser. Free, no watermark, no sign-up, and what you enter is not uploaded.
- [Hash Generator](https://hifreetools.com/developer/hash-generator): Generate SHA-256, SHA-1, SHA-384, or SHA-512 hashes from text instantly. In-browser tool with no data uploads—100% private.
- [Haversine Distance Calculator](https://hifreetools.com/developer/haversine-distance-calculator): Calculate the great-circle distance between two GPS coordinates using the Haversine formula. Get results in kilometers and miles instantly, no sign-up needed.
- [HSL to RGB Color Converter](https://hifreetools.com/developer/hsl-to-rgb-converter): Convert HSL (Hue, Saturation, Lightness) to RGB color values instantly. Free browser-based tool with hex output, color preview, and copy-ready CSS.
- [HTML Entity Encoder and Decoder](https://hifreetools.com/developer/html-entity-encoder): Free online HTML entity encoder and decoder. Convert &, <, >, ", and ' to named or numeric entities and decode entities back to plain text. 100% in-browser.
- [JSON Minifier](https://hifreetools.com/developer/json-minifier): Minify JSON in your browser: strip all whitespace, validate the syntax, and see original vs minified byte size and percent saved. Nothing is uploaded. Free.
- [JSON Validator](https://hifreetools.com/developer/json-validator): Validate JSON instantly and see exactly where the error is (line and column). Pretty-prints valid JSON. Runs in your browser — nothing uploaded.
- [JWT Decoder](https://hifreetools.com/developer/jwt-decoder): Decode JSON Web Tokens (JWTs) to view claims and timestamps in plain English. Free, in-browser, no upload. Verify token structure and expiration instantly.
- [Markdown to HTML Converter](https://hifreetools.com/developer/markdown-to-html): Convert Markdown to clean, sanitized HTML with a live preview. GitHub-flavored, copy-ready output, in your browser — never uploaded.
- [Number Base Converter](https://hifreetools.com/developer/number-base-converter): Convert numbers between binary (base 2), octal (base 8), decimal (base 10), and hexadecimal (base 16) instantly in your browser. Free, fast, no signup.
- [Pixels to REM Converter](https://hifreetools.com/developer/pixels-to-rem-converter): Convert pixels to REM instantly. Set any base font size (default 16px) and get the exact REM value for responsive CSS. Free, fast, no signup needed.
- [Regex Tester](https://hifreetools.com/developer/regex-tester): Free regex tester for JavaScript patterns. See all matches and counts live, with flags like g, i, m. Test before you code — 100% in your browser.
- [Relative Luminance Calculator](https://hifreetools.com/developer/relative-luminance-calculator): Calculate the relative luminance of any color using the WCAG 2.x formula. Enter an RGB or hex color to instantly get its luminance value for accessibility checks.
- [RFC 8259 — The JSON Data Interchange Format](https://hifreetools.com/developer/json-formatter): Format, validate, and minify JSON in your browser. Pinpoints syntax errors and pretty-prints with 2-space indents. Nothing you paste is uploaded. Free.
- [SQL Formatter](https://hifreetools.com/developer/sql-formatter): Format and beautify SQL queries with proper indentation and keyword casing, across MySQL, PostgreSQL, T-SQL and more. Free, in your browser, no upload.
- [Subnet (CIDR) Calculator](https://hifreetools.com/developer/subnet-calculator): Free subnet CIDR calculator. Enter an IP address and prefix length to instantly get network address, broadcast, subnet mask, first/last host, and usable host count.
- [Text to Binary Converter](https://hifreetools.com/developer/text-to-binary): Convert text to binary and binary back to text instantly in your browser. Also outputs decimal and hex. Full UTF-8 support, nothing uploaded. Free.
- [Unix Timestamp Converter](https://hifreetools.com/developer/timestamp-converter): Convert Unix timestamps (epoch) to human-readable dates and back, in UTC and your local time. Supports seconds and milliseconds. Free, in-browser.
- [URL Encoder & Decoder](https://hifreetools.com/developer/url-encoder): Encode and decode URLs and query parameters with percent-encoding, in your browser. Handles full Unicode (UTF-8). Free, private, no uploads.

## Finance Tools
- [Amortization Calculator](https://hifreetools.com/finance/amortization-calculator): Calculate your monthly loan payment, total interest, and a year-by-year amortization schedule from the loan amount, interest rate, and term. Free, in-browser.
- [APY Calculator](https://hifreetools.com/finance/apy-calculator): Free APY calculator. Convert a nominal annual rate and compounding frequency into the effective annual percentage yield, plus the interest earned on your balance.
- [Break-Even Calculator](https://hifreetools.com/finance/break-even-calculator): Calculate your break-even point in units and revenue instantly. Enter fixed costs, variable costs, and selling price to find when your business becomes profitable.
- [CAGR Calculator](https://hifreetools.com/finance/cagr-calculator): Calculate the compound annual growth rate (CAGR) of an investment from its beginning value, ending value and number of years, plus total growth, in your browser.
- [Car Loan Calculator](https://hifreetools.com/finance/car-loan-calculator): Estimate your monthly auto loan payment from vehicle price, down payment, trade-in, sales tax, APR and term — see loan amount, total paid and total interest.
- [Compound Interest Calculator](https://hifreetools.com/finance/compound-interest-calculator): Estimate how savings grow with compound interest and optional regular contributions. Free, shows the formula and the interest earned. Estimate only.
- [Credit Card Payoff Calculator](https://hifreetools.com/finance/credit-card-payoff-calculator): Find out how many months it takes to pay off a credit card with a fixed monthly payment, plus the total interest and total amount paid. Free, instant, in-browser.
- [Debt Payoff Calculator](https://hifreetools.com/finance/debt-payoff-calculator): Calculate exactly when you'll be debt-free and how much interest you'll pay. Compare avalanche vs snowball strategies with our free debt payoff calculator.
- [Discount Calculator](https://hifreetools.com/finance/discount-calculator): Calculate the sale price and how much you save from a percentage discount. Free, instant, with the formula shown. No sign-up required.
- [Down Payment Calculator](https://hifreetools.com/finance/down-payment-calculator): Calculate your home down payment from a price and percentage, or work out the percentage from a fixed dollar amount, and see the resulting loan amount and LTV.
- [Future Value Calculator](https://hifreetools.com/finance/future-value-calculator): Calculate the future value of a lump-sum investment with compound interest. Enter principal, rate, compounding frequency, and time to see your result instantly.
- [Hourly to Salary Calculator](https://hifreetools.com/finance/hourly-to-salary-calculator): Convert an hourly wage to annual, monthly, and weekly salary based on hours per week and weeks per year. Free, with the formula shown. Estimate only.
- [Inflation Calculator](https://hifreetools.com/finance/inflation-calculator): See how inflation changes prices and buying power over time. Enter an amount, a rate, and a number of years to get the future cost and today's value.
- [Investment Calculator](https://hifreetools.com/finance/investment-calculator): Project an investment's future value from a starting amount, monthly contributions, return rate and years — see total contributed vs growth. Free.
- [Investment Return Calculator](https://hifreetools.com/finance/investment-return-calculator): Calculate investment returns, future value, and ROI instantly. Enter your principal, contributions, rate, and time to see how your money grows.
- [Loan Payment Calculator](https://hifreetools.com/finance/loan-payment-calculator): Estimate the monthly payment, total cost, and total interest on a fixed-rate loan or mortgage. Free, shows the amortization formula. Estimate only.
- [Markup Calculator](https://hifreetools.com/finance/markup-calculator): Free markup calculator: enter cost and a selling price or markup % to get profit, markup percentage, margin percentage and price. See markup vs margin clearly.
- [Monthly Budget Calculator](https://hifreetools.com/finance/monthly-budget-calculator): Calculate your monthly budget instantly. Enter your income and expenses to see your savings rate, spending breakdown, and whether you're on track financially.
- [Mortgage Calculator](https://hifreetools.com/finance/mortgage-calculator): Estimate the full monthly mortgage payment — principal, interest, tax, insurance, PMI and HOA — with an amortization schedule and extra-payment savings.
- [Present Value Calculator](https://hifreetools.com/finance/present-value-calculator): Find the present value of a future sum of money. Enter the future value, discount rate and number of years to see today's worth and the total discount.
- [Price Per Unit Calculator](https://hifreetools.com/finance/price-per-unit-calculator): Calculate price per unit instantly to compare product value. Enter total price and quantity to find cost per ounce, pound, item, or any unit. Free online tool.
- [Profit Margin Calculator](https://hifreetools.com/finance/profit-margin-calculator): Calculate profit, profit margin, and markup from cost and selling price. Free, with the formulas shown — handy for pricing and ecommerce. Estimate only.
- [Retirement Savings Calculator](https://hifreetools.com/finance/retirement-calculator): Project your retirement nest egg from current savings, monthly contributions, expected return, and years left. See balance, total contributed, and growth.
- [ROI Calculator](https://hifreetools.com/finance/roi-calculator): Calculate return on investment instantly. Enter your initial cost and final return to get ROI percentage, net profit, and gain/loss in seconds.
- [Rule of 72 Calculator](https://hifreetools.com/finance/rule-of-72-calculator): Use the Rule of 72 calculator to find how long it takes to double your money or what rate you need. Instant browser results, no signup required.
- [Salary Calculator](https://hifreetools.com/finance/salary-calculator): Convert pay between hourly, daily, weekly, biweekly, monthly and annual — adjusting for hours and weeks worked. Free, instant, in your browser.
- [Salary to Hourly Calculator](https://hifreetools.com/finance/salary-to-hourly-calculator): Convert an annual salary to an equivalent hourly wage based on hours per week and weeks per year. Free, with the formula shown. Estimate only.
- [Sales Tax Calculator](https://hifreetools.com/finance/sales-tax-calculator): Add sales tax (or VAT/GST) to a price using a rate you enter, and see the tax amount and total. Free and instant. Enter your local rate.
- [Savings Goal Calculator](https://hifreetools.com/finance/savings-goal-calculator): Find how much to save each month to reach a goal by a target date, given a starting amount and interest rate. Free. Estimate only, not advice.
- [Simple Interest Calculator](https://hifreetools.com/finance/simple-interest-calculator): Calculate simple interest and the final amount from principal, rate, and time. Free, with the I = P × r × t formula shown. Estimate only.
- [Tip Calculator](https://hifreetools.com/finance/tip-calculator): Calculate the tip and total for any bill, and split it between people. Free, instant, with the simple formula shown. No sign-up.
- [VAT Calculator](https://hifreetools.com/finance/vat-calculator): Add VAT/GST to a net price or remove it from a gross price at any rate, with the net, VAT amount and gross shown. Free, instant, in your browser.

## Health & Fitness Tools
- [BMI Calculator](https://hifreetools.com/health/bmi-calculator): Calculate your Body Mass Index in metric or imperial units and see the WHO weight category. Free, shows the formula. General information, not medical advice.
- [BMR Calculator](https://hifreetools.com/health/bmr-calculator): Estimate your Basal Metabolic Rate (BMR) with the Mifflin-St Jeor formula, in metric or imperial units. Free. General information, not medical advice.
- [Body Fat Percentage Calculator](https://hifreetools.com/health/body-fat-calculator): Estimate your body fat percentage with the U.S. Navy tape-measure method in metric (cm). Free, shows the formula and a category. General info, not medical advice.
- [Body Surface Area (BSA) Calculator](https://hifreetools.com/health/body-surface-area): Estimate body surface area (BSA) in m² from height and weight using the Mosteller formula, with Du Bois as an alternative. Worked examples and sources.
- [Calorie Calculator (TDEE)](https://hifreetools.com/health/calorie-calculator): Estimate your daily calorie needs (TDEE) from BMR and activity level, in metric or imperial. Free. General information, not medical or diet advice.
- [Calories Burned Calculator](https://hifreetools.com/health/calories-burned-calculator): Estimate calories burned during exercise with the MET formula. Pick an activity, enter weight and minutes. Free. General info, not medical advice.
- [Daily Water Intake Calculator](https://hifreetools.com/health/water-intake-calculator): Calculate your daily water intake based on weight and activity level. Get personalized hydration targets in liters, milliliters, and fluid ounces instantly.
- [Heart Rate Zone Calculator](https://hifreetools.com/health/heart-rate-zone-calculator): Calculate your 5 heart rate training zones using the Karvonen formula. Enter your age and resting heart rate to find your aerobic, threshold, and max zones.
- [Ideal Body Weight (IBW) Calculator](https://hifreetools.com/health/ideal-body-weight): Estimate ideal body weight from height and sex with the Devine formula. A general population estimate, not medical advice — see how it works and its limits.
- [Lean Body Mass Calculator](https://hifreetools.com/health/lean-body-mass-calculator): Free lean body mass calculator using the Boer formula. Enter sex, weight, and height to get your LBM and body-fat mass in kg or lb instantly.
- [Macro Calculator](https://hifreetools.com/health/macro-calculator): Calculate your daily macronutrient targets — protein, carbs, and fat — based on your body stats, activity level, and fitness goal. Free, instant results.
- [One-Rep Max (1RM) Calculator](https://hifreetools.com/health/one-rep-max-calculator): Calculate your one-rep max (1RM) from any weight and rep count using the Epley formula. Free, instant, works in lbs or kg. General info, not medical advice.
- [Ovulation Calculator](https://hifreetools.com/health/ovulation-calculator): Estimate your ovulation day and fertile window from your last period and cycle length. Free, private, in your browser — general information only.
- [Pregnancy Due Date Calculator](https://hifreetools.com/health/due-date-calculator): Estimate your pregnancy due date from your last menstrual period using Naegele's rule, with cycle-length adjustment and trimester dates. Free, no sign-up.
- [Protein Intake Calculator](https://hifreetools.com/health/protein-intake-calculator): Calculate your daily protein target in grams from body weight and goal (0.8–2.0 g/kg). Free, shows the formula. General information, not medical advice.
- [Running Pace Calculator](https://hifreetools.com/health/running-pace-calculator): Calculate your running pace per km and per mile plus average speed from distance and finish time. Free and accurate — works for 5K, 10K, half and full marathon.
- [Sleep Calculator](https://hifreetools.com/health/sleep-calculator): Find the best bedtime or wake-up time using 90-minute sleep cycles, so you wake between cycles feeling refreshed. Free, instant, in your browser.
- [TDEE Calculator](https://hifreetools.com/health/tdee-calculator): Calculate your Total Daily Energy Expenditure (TDEE) from BMR and activity level using the Mifflin-St Jeor equation. Free, shows the math. General info only.
- [Waist-to-Hip Ratio Calculator](https://hifreetools.com/health/waist-to-hip-ratio-calculator): Calculate your waist-to-hip ratio (WHR) and see the WHO health-risk category by sex. Free, works in any unit. General information, not medical advice.
- [Walking Calorie Calculator](https://hifreetools.com/health/walking-calorie-calculator): Calculate calories burned walking based on your weight, speed, and duration. Uses MET values for slow, moderate, brisk, and fast walking. Free and instant.

## Image Tools
- [Base64 to Image Converter](https://hifreetools.com/image/base64-to-image): Decode a Base64 string or data URI back into an image and download it — all in your browser. Nothing is uploaded. Free, private, no sign-up.
- [Compress Image to KB](https://hifreetools.com/image/compress-image-to-kb): Compress a photo to a target size in KB (e.g. 50, 100, 200) by auto-searching JPEG quality, scaling only if needed. Free, in your browser, no upload.
- [Crop Image](https://hifreetools.com/image/crop-image): Crop a photo with a drag-and-resize box or a fixed aspect ratio (1:1, 4:3, 16:9), then download. Free, instant, and never uploaded — runs in your browser.
- [Favicon Generator](https://hifreetools.com/image/favicon-generator): Generate favicons at every standard size (16–512px, plus Apple touch icon) from one image. Free, instant, in your browser — never uploaded.
- [Flip Image](https://hifreetools.com/image/flip-image): Flip or mirror an image horizontally and vertically in your browser, then download it. Nothing is uploaded. Free, private, no sign-up.
- [GIF Maker](https://hifreetools.com/image/gif-maker): Combine several images into an animated GIF — set frame order, delay and size, then download. Free, in your browser, never uploaded.
- [HEIC to JPG Converter](https://hifreetools.com/image/heic-to-jpg): Convert iPhone HEIC/HEIF photos to JPG or PNG in your browser — batch convert, choose quality, never uploaded. Free, private, no sign-up.
- [Image Compressor](https://hifreetools.com/image/image-compressor): Compress JPG, PNG, and WebP images in your browser. Control quality, see the before/after size, and download — nothing is uploaded. Free, no sign-up.
- [Image Filters](https://hifreetools.com/image/image-filters): Apply brightness, contrast, saturation, grayscale, sepia, invert and blur to a photo with live sliders, then download. Free, in your browser, no upload.
- [Image Resizer](https://hifreetools.com/image/image-resizer): Resize images to exact pixel dimensions in your browser. Lock the aspect ratio, choose a format, and download — nothing is uploaded. Free, no sign-up.
- [Image to Base64 Converter](https://hifreetools.com/image/image-to-base64): Convert an image to a Base64 data URI in your browser, with ready CSS and HTML snippets to copy. Nothing is uploaded. Free, private, no sign-up.
- [JPG to PNG Converter](https://hifreetools.com/image/jpg-to-png): Convert JPG photos to lossless PNG in your browser. Batch convert and download instantly — nothing is uploaded. Free, private, no sign-up.
- [JPG to WebP Converter](https://hifreetools.com/image/jpg-to-webp): Convert JPG photos to smaller WebP in your browser. Batch convert, choose quality, and download — nothing is uploaded. Free, private, no sign-up.
- [Meme Generator](https://hifreetools.com/image/meme-generator): Make a classic meme: upload an image, add bold Impact-style top and bottom captions, and download. Free, no watermark, runs in your browser.
- [Pixelate Image](https://hifreetools.com/image/pixelate-image): Pixelate or mosaic a photo to censor faces and private details, with an adjustable block size. Free, instant, in your browser — never uploaded.
- [PNG to JPG Converter](https://hifreetools.com/image/png-to-jpg): Convert PNG images to JPG in your browser. Batch convert, pick the quality, and download — nothing is uploaded. Free, private, no sign-up.
- [PNG to WebP Converter](https://hifreetools.com/image/png-to-webp): Convert PNG images to smaller WebP in your browser, keeping transparency. Batch convert and download — nothing is uploaded. Free, no sign-up.
- [Rotate Image](https://hifreetools.com/image/rotate-image): Rotate an image left or right by 90°, 180°, or 270° in your browser, then download it. Nothing is uploaded. Free, private, no sign-up.
- [SVG to PNG Converter](https://hifreetools.com/image/svg-to-png): Convert SVG to PNG at any width with transparency preserved. Paste SVG code or upload a file; renders instantly in your browser, never uploaded.
- [Watermark Image](https://hifreetools.com/image/watermark-image): Add a text watermark to a photo — choose position, opacity, color and size, or tile it across the whole image. Free, in your browser, never uploaded.
- [WebP to JPG Converter](https://hifreetools.com/image/webp-to-jpg): Convert WebP images to JPG in your browser. Batch convert, choose the quality, and download — nothing is uploaded. Free, private, no sign-up.
- [WebP to PNG Converter](https://hifreetools.com/image/webp-to-png): Convert WebP images to PNG in your browser, keeping transparency. Batch convert and download — nothing is uploaded. Free, private, no sign-up.

## Color & Design Tools
- [Color Contrast Checker](https://hifreetools.com/color/color-contrast-checker): Check if text and background colors meet WCAG AA and AAA accessibility standards. Instant contrast ratio calculator with live preview.
- [Color Converter](https://hifreetools.com/color/color-converter): Convert a color between HEX, RGB, HSL, HSV, and CMYK instantly. Type any format and copy all the others, with a live swatch. Free, in your browser.
- [Color Picker](https://hifreetools.com/color/color-picker): Pick a color visually and copy its HEX, RGB, HSL, HSV, and CMYK codes. Adjust with a picker and sliders, with a live preview. Free, in your browser.
- [Color Shades & Tints Generator](https://hifreetools.com/color/color-shades-generator): Generate lighter tints and darker shades of any base color, each with a copyable HEX code. Build palettes and variants instantly in your browser.
- [HEX to RGB Converter](https://hifreetools.com/color/hex-to-rgb): Instantly convert HEX color codes to RGB values. Supports #RRGGBB and #RGB formats. See RGB output, HSL values, and live color preview.
- [Image Color Palette Extractor](https://hifreetools.com/color/image-palette-extractor): Upload an image to extract its dominant color palette and average color, each as a copyable HEX. Free, private — runs entirely in your browser.
- [Image Color Picker](https://hifreetools.com/color/image-color-picker): Upload an image and click any pixel to read its exact HEX and RGB color. Free, private, and runs in your browser — your photo is never uploaded.
- [Random Color Generator](https://hifreetools.com/color/random-color-generator): Generate a random color instantly and copy its HEX, RGB, and HSL values. Click Generate for a fresh color or a small random palette. Free, fast, browser-based.
- [RGB to HEX Converter](https://hifreetools.com/color/rgb-to-hex): Convert RGB colors to HEX codes instantly. Enter red, green, blue values (0-255) and get the hex code, plus HSL values and live color swatch.

## Date & Time Tools
- [Add or Subtract Days Calculator](https://hifreetools.com/date-time/add-subtract-days-calculator): Instantly add or subtract any number of days from a date. Get the exact future or past date with our free online Add or Subtract Days Calculator.
- [Age Calculator](https://hifreetools.com/date-time/age-calculator): Calculate your exact age in years, months, and days from your date of birth, plus total days and days until your next birthday. Free, in-browser.
- [Business Days Calculator](https://hifreetools.com/date-time/business-days-calculator): Count business days (Mon–Fri) between two dates, or add/subtract workdays from a date. Excludes weekends. Free, instant, runs in your browser.
- [Countdown Timer](https://hifreetools.com/date-time/countdown-timer): A free online countdown timer. Set hours, minutes, and seconds, then start, pause, and reset. It beeps when time is up. Runs in your browser, no sign-up.
- [Countdown to Date](https://hifreetools.com/date-time/countdown-to-date): Live countdown to any future date and time, showing days, hours, minutes, and seconds remaining. Free and updates every second in your browser.
- [Countdown to Date Calculator](https://hifreetools.com/date-time/countdown-days-calculator): Calculate exactly how many days, weeks, and months remain until any future date — or how many days have passed since a past date. Free, instant, no sign-up.
- [Date Difference Calculator](https://hifreetools.com/date-time/date-difference-calculator): Calculate the time between two dates in years, months, and days, plus the total number of days and weeks. Free, exact, runs in your browser.
- [Day of the Week Calculator](https://hifreetools.com/date-time/day-of-week-calculator): Find what day of the week any date falls on — past, present, or future. Instant results for birthdays, holidays, historical events, and more.
- [Days Until Calculator](https://hifreetools.com/date-time/days-until-calculator): Count the days until any future date — a holiday, deadline, birthday, or event. Free countdown showing days and weeks. Runs in your browser.
- [Online Stopwatch](https://hifreetools.com/date-time/stopwatch): A free online stopwatch with start, stop, reset, and lap times. Counts up to the centisecond, runs in your browser with no sign-up. Fast and accurate.
- [Time Duration Calculator](https://hifreetools.com/date-time/time-duration-calculator): Calculate the exact duration between two times or dates. Get results in hours, minutes, seconds, and days instantly. Free online time duration calculator.
- [Time Zone Converter](https://hifreetools.com/date-time/time-zone-converter): Convert a date and time between any two time zones, with daylight saving handled automatically. Free, accurate, and runs in your browser. No sign-up.
- [Week Number Calculator](https://hifreetools.com/date-time/week-number-calculator): Find the ISO 8601 week number for any date, and the date range for a given week number and year. Free, accurate, runs in your browser. No sign-up.
- [Work Hours Calculator](https://hifreetools.com/date-time/work-hours-calculator): Calculate exact hours and minutes worked between a start time and end time, subtract break time, and see daily or weekly totals. Free, runs in your browser.
- [World Clock & Time Zone Converter](https://hifreetools.com/date-time/world-clock): See the current time in any city or time zone worldwide. Compare multiple cities side-by-side and convert a specific time from one zone to another instantly.

## Random Generators
- [Coin Flip](https://hifreetools.com/random/coin-flip): Flip a virtual coin for a fair heads-or-tails result, with a running tally of your flips. Free, instant, and fair — runs in your browser.
- [Dice Roller](https://hifreetools.com/random/dice-roller): Roll virtual dice online — choose the number of dice and sides (D4, D6, D20, D100). Fair results with a total. Free, in-browser, no app needed.
- [Random Number Generator](https://hifreetools.com/random/random-number-generator): Generate random numbers in any range, one or many, with options for no duplicates and sorting. Fair and secure, runs in your browser. Free.
- [Random Picker](https://hifreetools.com/random/random-picker): Paste a list and pick one or more items at random — fairly and instantly. Options to remove duplicates and pick without repeats. Free, in your browser.
- [Yes or No Generator](https://hifreetools.com/random/yes-no-generator): Get a random yes or no answer to help make a quick decision, with an optional ‘maybe’. Fair 50/50 result in your browser. Free, no sign-up.

## Security Tools
- [NIST SP 800-63B — Digital Identity Guidelines (authentication)](https://hifreetools.com/security/password-generator): Generate strong, random passwords in your browser using the Web Crypto API. Choose length and character types. Nothing is sent or stored. Free.
- [RFC 9562 — Universally Unique IDentifiers (UUIDs)](https://hifreetools.com/security/uuid-generator): Generate random version-4 UUIDs in your browser, one or many at a time, and copy them instantly. Cryptographically random, never uploaded. Free.

## SEO & Marketing Tools
- [Keyword Density Checker](https://hifreetools.com/seo/keyword-density-checker): Analyze any text for keyword frequency and density — one, two, or three-word phrases, with common words filtered out. Free, instant, in your browser.
- [Meta Description Length Checker](https://hifreetools.com/seo/meta-description-checker): Check meta description length and see how your text appears in Google search results. Get real-time feedback on optimal SEO length (120-160 characters).
- [Meta Tag Generator](https://hifreetools.com/seo/meta-tag-generator): Generate clean HTML meta tags — title, description, robots, canonical, theme-color — with live length checks. Copy-paste ready, free, in your browser.
- [Meta Title Length Checker](https://hifreetools.com/seo/meta-title-checker): Check if your SEO title fits Google's display limit (~50–60 characters). See a live SERP preview and get feedback instantly. Free, in-browser, private.
- [Open Graph Generator](https://hifreetools.com/seo/open-graph-generator): Generate Open Graph and Twitter Card meta tags with a live share-preview card. Control title, image, URL and type, then copy-paste. Free, in your browser.
- [Robots.txt Generator](https://hifreetools.com/seo/robots-txt-generator): Build a valid robots.txt file — allow or block crawlers, set per-path disallow rules, crawl-delay and a sitemap line. Copy or save, free, in your browser.
- [UTM Link Builder](https://hifreetools.com/seo/utm-builder): Free UTM parameter builder. Add utm_source, utm_medium, utm_campaign, utm_term, and utm_content to any URL for accurate marketing analytics. Works in browser.

## Science & Engineering Tools
- [Acceleration Calculator](https://hifreetools.com/science/acceleration-calculator): Free acceleration calculator using a = (v − u) / t. Enter initial velocity, final velocity, and time to get acceleration in m/s² instantly, with worked steps.
- [Battery Capacity (mAh) Calculator](https://hifreetools.com/science/battery-capacity-calculator): Free battery capacity calculator. Enter capacity (mAh), voltage, and current draw to find runtime in hours, energy in Wh, or required mAh for a target life.
- [Buoyancy Force Calculator](https://hifreetools.com/science/buoyancy-calculator): Calculate buoyancy force instantly using Archimedes' principle. Enter fluid density, gravity, and submerged volume to find the upward buoyant force in Newtons.
- [Capacitive Reactance Calculator](https://hifreetools.com/science/capacitive-reactance-calculator): Calculate capacitive reactance Xc = 1/(2π·f·C) in ohms. Enter frequency in Hz and capacitance in µF to get reactance instantly, with worked examples and the formula.
- [Capacitor Energy Calculator](https://hifreetools.com/science/capacitor-energy-calculator): Calculate energy stored in a capacitor with E = ½CV². Enter capacitance in µF and voltage to get energy in joules and millijoules, plus stored charge.
- [Centripetal Force Calculator](https://hifreetools.com/science/centripetal-force-calculator): Free centripetal force calculator: enter mass, speed and radius to instantly get the inward force (N) and centripetal acceleration (m/s²) from F = mv²/r.
- [Circular Motion Calculator](https://hifreetools.com/science/circular-motion-calculator): Calculate centripetal acceleration, centripetal force, period, frequency, and angular velocity for circular motion. Instant results with formulas.
- [Combined Gas Law Calculator](https://hifreetools.com/science/combined-gas-law): Solve P1V1/T1 = P2V2/T2 for any unknown pressure, volume, or temperature. Includes Boyle's, Charles's, and Gay-Lussac's law special cases with worked examples.
- [Decibel Calculator](https://hifreetools.com/science/decibel-calculator): Free decibel calculator: find gain or loss in dB from a power ratio (10·log₁₀) or voltage/amplitude ratio (20·log₁₀). Instant, accurate, works offline in your browser.
- [Density Calculator](https://hifreetools.com/science/density-calculator): Free density calculator. Enter any two of mass, volume, or density and solve the third using ρ = m / V. Results in kg/m³ and g/cm³, no signup.
- [Dilution Calculator](https://hifreetools.com/science/dilution-calculator): Free dilution calculator using C1V1 = C2V2. Enter any three of initial concentration, initial volume, final concentration or final volume to solve the fourth.
- [Dynamic Pressure Calculator](https://hifreetools.com/science/dynamic-pressure-calculator): Free dynamic pressure calculator. Enter fluid density (kg/m³) and velocity (m/s) to get dynamic pressure q in pascals and kilopascals using q = ½ x ρ x v².
- [Flow Rate Calculator](https://hifreetools.com/science/flow-rate-calculator): Free volumetric flow rate calculator. Enter cross-sectional area and fluid velocity to get flow rate Q = A·v instantly in m³/s and L/s, with worked examples.
- [Force Calculator](https://hifreetools.com/science/force-calculator): Free force calculator using Newton's second law F = m·a. Enter any two of force, mass, and acceleration to solve the third, with worked examples and steps.
- [Free Fall Calculator](https://hifreetools.com/science/free-fall-calculator): Free fall calculator: find fall time, impact velocity, or drop height from rest using g = 9.80665 m/s². Enter time or height for instant, accurate results.
- [Friction Calculator](https://hifreetools.com/science/friction-calculator): Free friction force calculator using Ff = μ·N. Enter the coefficient of friction and normal force to get friction force in newtons, with worked examples.
- [Gear Ratio Calculator](https://hifreetools.com/science/gear-ratio-calculator): Free gear ratio calculator. Enter driver and driven teeth to get the gear ratio, output RPM and torque multiplier instantly, with worked examples and formulas.
- [Half-Life Calculator](https://hifreetools.com/science/half-life-calculator): Free half-life calculator for radioactive decay. Enter initial amount, half-life, and elapsed time to get remaining amount, percent remaining, and number of half-lives.
- [Heat Engine Efficiency Calculator](https://hifreetools.com/science/heat-engine-efficiency-calculator): Free Carnot heat engine efficiency calculator. Enter hot and cold reservoir temperatures in kelvin to find the maximum theoretical efficiency η = 1 − Tc/Th.
- [Hooke's Law Calculator](https://hifreetools.com/science/hookes-law-calculator): Free Hooke's law calculator: enter any two of force, spring constant, or displacement to solve F = kx instantly, plus elastic potential energy ½kx².
- [Ideal Gas Law Calculator](https://hifreetools.com/science/ideal-gas-law): Solve PV = nRT for pressure, volume, moles, or temperature. Uses R = 8.314 J/(mol·K), accepts SI units, and shows worked examples with steps.
- [Inductive Reactance Calculator](https://hifreetools.com/science/inductive-reactance-calculator): Free inductive reactance calculator: enter frequency and inductance to get Xl = 2πfL in ohms instantly. Worked examples, formula, and AC circuit tips.
- [Kinetic Energy Calculator](https://hifreetools.com/science/kinetic-energy-calculator): Free kinetic energy calculator. Enter mass (kg) and velocity (m/s) to get kinetic energy in joules and kilojoules plus momentum, using KE = ½ x m x v².
- [LED Resistor Calculator](https://hifreetools.com/science/led-resistor-calculator): Free LED series resistor calculator. Enter supply voltage, LED forward voltage and current to get the exact resistor (Ω) and its power rating (W).
- [Mechanical Efficiency Calculator](https://hifreetools.com/science/mechanical-efficiency-calculator): Calculate mechanical efficiency instantly. Enter input and output work or power to find η (%). Includes formula, worked examples, and unit tips.
- [Molarity Calculator](https://hifreetools.com/science/molarity-calculator): Free molarity calculator. Enter any two of moles, volume, or molarity and instantly solve the third using M = moles ÷ liters. Worked examples included.
- [Mole Calculator](https://hifreetools.com/science/mole-calculator): Free mole calculator: solve moles, mass, or molar mass from n = mass ÷ molar mass, and get particle counts via Avogadro's number. Instant, no sign-up.
- [Momentum Calculator](https://hifreetools.com/science/momentum-calculator): Free momentum calculator: find linear momentum p = m·v from mass and velocity, plus optional impulse J = F·Δt. Instant kg·m/s results, formula shown.
- [Ohm's Law Calculator](https://hifreetools.com/science/ohms-law): Free Ohm's Law calculator. Enter any two of voltage, current or resistance to solve the rest plus power, using V = I x R and P = V x I.
- [Parallel Resistance Calculator](https://hifreetools.com/science/parallel-resistance-calculator): Calculate the total resistance of up to four resistors wired in parallel using 1/Rt = Σ(1/Ri). Free, instant, and also shows the series sum for reference.
- [Percent Yield Calculator](https://hifreetools.com/science/percent-yield-calculator): Free percent yield calculator: divide actual yield by theoretical yield and multiply by 100. Instantly check reaction efficiency for chemistry labs and homework.
- [pH Calculator](https://hifreetools.com/science/ph-calculator): Free pH calculator. Enter pH or the hydrogen ion concentration [H+] in mol/L to find pH, [H+], pOH, and [OH-] using pH = -log10[H+]. Worked examples included.
- [Potential Energy Calculator](https://hifreetools.com/science/potential-energy-calculator): Calculate gravitational potential energy with PE = m·g·h. Enter mass, height, and gravity to get the result in joules and kilojoules instantly. Free, accurate.
- [Power Calculator](https://hifreetools.com/science/power-calculator): Free power calculator: find power in watts and horsepower from work and time (P = W/t) or force and velocity (P = F·v). Instant, accurate, browser-based.
- [Power Dissipation Calculator](https://hifreetools.com/science/power-dissipation-calculator): Free power dissipation calculator. Enter any two of voltage, current, and resistance to get the power in watts plus the missing quantity, with worked steps.
- [Pressure Calculator](https://hifreetools.com/science/pressure-calculator): Free pressure calculator. Enter any two of force (N), area (m²) or pressure (Pa) to solve the third, using P = F / A. Results shown in pascals and kilopascals.
- [Projectile Motion Calculator](https://hifreetools.com/science/projectile-motion-calculator): Free projectile motion calculator: enter launch speed and angle to get range, maximum height, and time of flight on flat ground using g = 9.80665 m/s².
- [RC Time Constant Calculator](https://hifreetools.com/science/rc-time-constant-calculator): Free RC time constant calculator. Enter resistance (Ω) and capacitance (µF) to get τ = R·C in seconds and ms, plus the 5τ full charge time, with worked examples.
- [Resistor Color Code Calculator](https://hifreetools.com/science/resistor-color-code): Decode 4-band and 5-band resistor color codes into resistance (Ω, kΩ, MΩ) and tolerance. Pick each band's color and read the exact value, range, and percent.
- [Reynolds Number Calculator](https://hifreetools.com/science/reynolds-number-calculator): Free Reynolds number calculator: enter density, velocity, length, and viscosity to get Re = ρvL/μ instantly and see if flow is laminar, transitional, or turbulent.
- [Scientific Calculator](https://hifreetools.com/science/scientific-calculator): Free online scientific calculator: trigonometry, logarithms, exponents, powers, roots, factorials, π, e, memory, and DEG/RAD/GRAD. In your browser.
- [Specific Heat Calculator](https://hifreetools.com/science/specific-heat-calculator): Free specific heat calculator: find heat energy Q from mass, specific heat capacity, and temperature change using Q = mcΔT. Instant answers in joules and kJ.
- [Spring Potential Energy Calculator](https://hifreetools.com/science/spring-potential-energy-calculator): Calculate spring potential energy instantly using Hooke's Law. Enter spring constant (k) and displacement (x) to get elastic potential energy in joules.
- [Stress Strain Calculator](https://hifreetools.com/science/stress-strain-calculator): Free stress strain calculator: enter force, area, length, and elongation to get stress (Pa/MPa), strain (%), and Young's modulus (Pa/GPa) instantly.
- [Thermal Expansion Calculator](https://hifreetools.com/science/thermal-expansion-calculator): Free linear thermal expansion calculator. Enter length, coefficient α, and temperature change to find ΔL and the new length using ΔL = α·L₀·ΔT.
- [Torque Calculator](https://hifreetools.com/science/torque-calculator): Free torque calculator. Enter force, lever arm length and angle to find torque τ = F × r × sin(θ) in N·m, with worked examples and unit conversions.
- [Transformer Turns Ratio Calculator](https://hifreetools.com/science/transformer-turns-ratio-calculator): Calculate transformer turns ratio, secondary voltage, current, and winding turns instantly. Free online tool for step-up and step-down transformers.
- [Voltage Divider Calculator](https://hifreetools.com/science/voltage-divider-calculator): Calculate the output voltage of a resistive voltage divider from Vin, R1, and R2. Get Vout and the divider current in amps and milliamps instantly, with the formula.
- [Wave Equation Calculator](https://hifreetools.com/science/wave-equation-calculator): Calculate wave speed, frequency, or wavelength instantly. Enter any two known values and solve v = fλ for sound, light, radio, and ocean waves.
- [Wavelength Frequency Calculator](https://hifreetools.com/science/wavelength-frequency-calculator): Convert between wavelength and frequency for light or any wave using c = λ·f. Enter wavelength in meters or frequency in Hz; editable wave speed. Free and instant.
- [Work Calculator](https://hifreetools.com/science/work-calculator): Free physics work calculator using W = F·d·cos θ. Enter force, distance, and angle to find work done in joules, with worked examples and clear steps.

## Guides
- [APR vs APY: Understanding the Difference Between Interest Rates](https://hifreetools.com/guides/apr-vs-apy): Learn the difference between APR and APY, how compound interest makes APY higher, and where each applies. Includes formulas and real-world examples.
- [Simple vs Compound Interest: Formulas, Comparison, and Real-World Applications](https://hifreetools.com/guides/simple-vs-compound-interest): The difference between simple and compound interest — with formulas, a 10-year worked example, and why compounding dominates savings and loans.
- [How to Calculate Percentage Change](https://hifreetools.com/guides/how-to-calculate-percentage-change): How to calculate percentage change, increase, and decrease — with formulas, worked examples, and the percent-change vs percentage-points difference.
- [Metric vs Imperial Units: History, Differences, and Conversion Guide](https://hifreetools.com/guides/metric-vs-imperial-units): Learn the key differences between metric and imperial systems, why the US uses imperial, and exact conversion factors for length, weight, temperature, and more.
- [Understanding BMI](https://hifreetools.com/guides/understanding-bmi): Learn what Body Mass Index (BMI) measures, the WHO weight categories, the exact formula, and why it's a screening tool—not a diagnosis. Includes limitations.
- [How Loan Amortization Works](https://hifreetools.com/guides/how-loan-amortization-works): How loan amortization splits each payment between principal and interest, why early payments are mostly interest, and how extra payments save money.
- [Mean vs Median vs Mode: Definitions, Formulas, and When to Use Each](https://hifreetools.com/guides/mean-median-mode): Learn the difference between mean, median, and mode. Understand formulas, worked examples with real salary data, and how outliers affect each measure.
- [What is Base64? Encoding Explained](https://hifreetools.com/guides/what-is-base64): Learn what Base64 encoding is, how it works, and why it's not encryption. Covers 33% size increase, data URIs, JWT, and email attachments.
- [How to Convert Kilograms to Pounds (and Back)](https://hifreetools.com/guides/how-to-convert-kg-to-lbs): Convert kg to lbs with the exact factor (1 kg = 2.20462 lb), a quick ×2.2 mental trick, a reference table, and common mistakes to avoid.
- [JSON Formatter vs JSON Validator: What's the Difference?](https://hifreetools.com/guides/json-formatter-vs-validator): A JSON formatter pretty-prints and indents data; a validator checks syntax and locates errors. When to use each, and what valid JSON requires.
- [How UTM Parameters Work (with Examples)](https://hifreetools.com/guides/how-utm-parameters-work): How the five UTM parameters (source, medium, campaign, term, content) tag links so analytics can credit traffic — with examples and a tag table.
- [How to Calculate a Tip (and Split the Bill)](https://hifreetools.com/guides/how-to-calculate-a-tip): Learn how to calculate a tip, what percentage to leave in different situations, how to split a bill among friends, and whether to tip on pre-tax or total.
- [What Makes a Strong Password](https://hifreetools.com/guides/what-makes-a-strong-password): Learn what actually makes a password strong: why length beats complexity, how passphrases work, and the current NIST SP 800-63B guidance on resets and rules.
- [How to Compress an Image Without Losing Quality](https://hifreetools.com/guides/how-to-compress-images-without-losing-quality): Learn how to compress images without visible quality loss: lossy vs lossless, JPEG vs PNG vs WebP, when to resize, quality sliders, and stripping metadata.
- [HEX, RGB, and HSL Color Codes Explained](https://hifreetools.com/guides/hex-rgb-hsl-color-codes-explained): Understand HEX, RGB, and HSL color notation: what each one means, how they convert, when to use each, and how alpha controls opacity.
- [Kitchen Conversions: Cups, Milliliters, Liters, and Gallons](https://hifreetools.com/guides/kitchen-volume-conversions): Convert cups, tablespoons, fluid ounces, milliliters, liters, and gallons. Learn US vs metric vs imperial units and why kitchen measurements differ.
- [URL Encoding (Percent-Encoding) Explained](https://hifreetools.com/guides/url-encoding-explained): Learn how URL percent-encoding works: reserved vs unreserved characters, when to encode query parameters, and common gotchas with spaces, &, +, and #.

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## En Español (Spanish)
- [Conversores (índice)](https://hifreetools.com/es/converters)
- [miles-to-feet](https://hifreetools.com/es/converters/miles-to-feet)
- [nautical-miles-to-km](https://hifreetools.com/es/converters/nautical-miles-to-km)
- [meters-to-yards](https://hifreetools.com/es/converters/meters-to-yards)
- [celsius-to-kelvin](https://hifreetools.com/es/converters/celsius-to-kelvin)
- [kelvin-to-celsius](https://hifreetools.com/es/converters/kelvin-to-celsius)
- [fahrenheit-to-kelvin](https://hifreetools.com/es/converters/fahrenheit-to-kelvin)
- [knots-to-mph](https://hifreetools.com/es/converters/knots-to-mph)
- [ms-to-kmh](https://hifreetools.com/es/converters/ms-to-kmh)
- [acres-to-square-feet](https://hifreetools.com/es/converters/acres-to-square-feet)
- [hectares-to-acres](https://hifreetools.com/es/converters/hectares-to-acres)
- [square-km-to-square-miles](https://hifreetools.com/es/converters/square-km-to-square-miles)
- [calories-to-kilojoules](https://hifreetools.com/es/converters/calories-to-kilojoules)
- [bar-to-psi](https://hifreetools.com/es/converters/bar-to-psi)
- [kpa-to-psi](https://hifreetools.com/es/converters/kpa-to-psi)
- [mpa-to-psi](https://hifreetools.com/es/converters/mpa-to-psi)
- [cubic-meters-to-liters](https://hifreetools.com/es/converters/cubic-meters-to-liters)
- [feet-to-inches](https://hifreetools.com/es/converters/feet-to-inches)
- [ml-to-cups](https://hifreetools.com/es/converters/ml-to-cups)
- [tablespoons-to-ml](https://hifreetools.com/es/converters/tablespoons-to-ml)
- [teaspoons-to-ml](https://hifreetools.com/es/converters/teaspoons-to-ml)
- [fluid-ounces-to-ml](https://hifreetools.com/es/converters/fluid-ounces-to-ml)
- [pints-to-liters](https://hifreetools.com/es/converters/pints-to-liters)
- [quarts-to-liters](https://hifreetools.com/es/converters/quarts-to-liters)
- [kg-to-stones](https://hifreetools.com/es/converters/kg-to-stones)
- [grams-to-pounds](https://hifreetools.com/es/converters/grams-to-pounds)
- [yards-to-meters](https://hifreetools.com/es/converters/yards-to-meters)
- [psi-to-bar](https://hifreetools.com/es/converters/psi-to-bar)
- [kilojoules-to-calories](https://hifreetools.com/es/converters/kilojoules-to-calories)
- [lbs-to-kg](https://hifreetools.com/es/converters/lbs-to-kg)
- [inches-to-cm](https://hifreetools.com/es/converters/inches-to-cm)
- [fahrenheit-to-celsius](https://hifreetools.com/es/converters/fahrenheit-to-celsius)
- [km-to-miles](https://hifreetools.com/es/converters/km-to-miles)
- [feet-to-meters](https://hifreetools.com/es/converters/feet-to-meters)
- [ounces-to-grams](https://hifreetools.com/es/converters/ounces-to-grams)
- [gallons-to-liters](https://hifreetools.com/es/converters/gallons-to-liters)
- [kmh-to-mph](https://hifreetools.com/es/converters/kmh-to-mph)
- [cups-to-ml](https://hifreetools.com/es/converters/cups-to-ml)
- [kg-to-grams](https://hifreetools.com/es/converters/kg-to-grams)
- [mph-to-ms](https://hifreetools.com/es/converters/mph-to-ms)
- [square-feet-to-square-meters](https://hifreetools.com/es/converters/square-feet-to-square-meters)

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