A growing collection of free utilities — calculators, converters, and generators that work right in your browser. No sign-up, no install.
Calculate your Body Mass Index in metric or imperial units, with category interpretation.
Estimate your daily calorie needs using the Mifflin-St Jeor BMR formula and an activity multiplier. Includes targets for weight loss and gain.
Estimate ideal body weight using four classic clinical formulas plus the WHO healthy BMI range. Choose by height and sex.
Estimate your pregnancy due date from the last menstrual period or conception date. Includes gestational weeks and trimester.
Estimate your recommended daily water intake based on body weight and activity level. Shown in liters, ounces, cups, and bottle equivalents.
Calculate running pace from distance and time, or finish time from a target pace. Output per-km, per-mile, km/h, and mph.
Calculate daily protein, fat, and carb targets from your TDEE and weight goal. Uses 30/30/40 split with a protein floor of 1.6 g/kg.
Convert between metric and imperial length units instantly. Includes mm, cm, m, km, inches, feet, yards, and miles.
Convert between Celsius, Fahrenheit, Kelvin, and Rankine. All four scales update at once.
Convert between metric and imperial mass units. Includes mg, grams, kilograms, tonnes, ounces, pounds, and stones.
Convert between metric, imperial, and Japanese area units. Includes m², km², hectare, ft², acre, mile², and tsubo.
Convert between time units from milliseconds to years. Months use the average length, years use the Julian definition.
Convert digital storage sizes between bytes, kilobytes, megabytes, gigabytes, terabytes, and petabytes. Switch between SI (1000) and IEC binary (1024).
Convert between metric and US/UK volume units. Includes mL, liters, m³, teaspoons, tablespoons, fluid ounces, cups, pints, quarts, and gallons.
Convert between common speed units: km/h, mph, m/s, ft/s, knots, and Mach. Used for vehicles, weather, aviation, and physics.
Convert vehicle fuel economy between mpg (US), mpg (UK), km per liter, and L per 100 km. Distinguishes US and UK gallons.
Calculate exact age in years, months, days, weeks, and hours from any birth date to any target date.
Live countdown to any future date and time. Updates every second; works for events, deadlines, launches, vacations.
Convert between Unix timestamps (seconds or milliseconds) and human-readable dates. Shows ISO 8601, local time, and relative time.
Add or subtract years/months/days from a date, or find the precise difference between two dates including business days.
Convert one moment in time across multiple timezones at once. Add or remove zones; great for scheduling international meetings.
Test cron expressions and see the next 5 scheduled runs in your local timezone. Validates fields, supports ranges, lists, and steps.
Three percentage calculators in one: 'X% of Y', 'X is what % of Y', and percentage change between two values.
Calculate your GPA on the 4.0 scale, weighted by course credit hours. Add as many courses as you need.
Convert numbers between binary, octal, decimal, and hexadecimal. Validates input for the chosen base and shows all four representations.
Generate random integers in any range using your browser's secure random API. Optionally enforce uniqueness for lottery, raffle, or sample-without-replacement use cases.
Calculate how much paint you need based on room dimensions, number of coats, and doors/windows. Output in liters or gallons.
Calculate width or height to preserve a target aspect ratio. Common ratios (16:9, 9:16, 1:1, 4:3, 21:9) one-click presets included.
Calculate tip and split a restaurant bill across any number of people. Quick presets for common tip percentages.
See how an investment grows over time with compounding interest and optional monthly contributions. Customizable compounding frequency.
Calculate the monthly payment for any fixed-rate loan, plus total amount paid and total interest over the life of the loan.
Add sales tax to a pre-tax amount or extract the tax from a tax-inclusive total. Works for any tax rate (sales tax, VAT, GST).
Calculate the final price after a percentage discount, plus optional sales tax. See how much you saved at a glance.
Calculate the full monthly mortgage payment including principal, interest, property tax, insurance, PMI (if applicable), and HOA fees.
Calculate sell price, gross profit, and gross margin from cost and markup percentage. Distinguishes markup vs margin clearly.
Compare items by unit price (price per gram, ounce, count, etc.). Add as many items as you want; the cheapest is highlighted.
Validate a credit card number's checksum (Luhn algorithm) and detect the issuing brand. Browser-only — your card number never leaves your device.
Generate strong random passwords using your browser's secure crypto API. Configurable length, character sets, and ambiguity filter.
Count words, characters, sentences, paragraphs, plus estimated reading and speaking time. Handles CJK languages correctly.
Convert text into 10 case styles: UPPER, lower, Title, Sentence, camelCase, PascalCase, snake_case, kebab-case, CONSTANT_CASE, and inverted.
Encode any UTF-8 text to Base64 or decode it back. Toggle URL-safe encoding for use in URLs and JWTs.
Pretty-print or minify JSON. Validates the input and shows a clear error with line and column on failure.
Generate placeholder Latin text by paragraphs, sentences, or word count. Optional 'Lorem ipsum' opening line.
Encode any text into URL percent-encoding or decode an encoded string back. UTF-8 safe — handles emoji and CJK characters correctly.
Convert Arabic numbers to Roman numerals (and back). Validates canonical form so VIIII won't be silently accepted as 9.
Generate cryptographically random UUID v4 or time-ordered UUID v7. Bulk-generate up to 100 at a time with one-click copy.
Compare two blocks of text line by line. Added, removed, and unchanged lines are color-coded with line numbers.
Test JavaScript regular expressions interactively. See live highlighted matches, capture groups, and a replace preview.
Count how often each character or word appears in your text. Sortable, with percentages, and optional case sensitivity.
Compute SHA-1, SHA-256, SHA-384, and SHA-512 hashes of any UTF-8 text. Browser-native Web Crypto API; nothing leaves your device.
Validate email address syntax against RFC 5322 and detect common typos in popular providers (gmail, yahoo, hotmail, etc).
Replace text with literal find/replace or full regex. Toggle case sensitivity and multi-line mode. Match count shown live.
Convert colors between HEX, RGB, and HSL with a live preview swatch. Edit any field; the others update.
Check the color contrast ratio between text and background. Shows live preview and pass/fail badges for WCAG AA and AAA at normal and large text sizes.
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