Free online calculators and converters

57 tools that do one thing each and do it immediately. No sign-up, no installation, and almost all of them run entirely in your browser.

• Percentage Calculator - Work out what X% of Y is, what percentage one number is of another, and percentage increase or decrease. Four calculators, instant answers, worked formulas.
• Grade Calculator - Work out your current weighted grade and exactly what score you need on the final exam to reach the grade you are aiming for.
• Fraction Calculator - Add, subtract, multiply and divide fractions with results reduced automatically, plus conversion between decimals, fractions and mixed numbers.
• Ratio Calculator - Solve a proportion for a missing value, simplify a ratio to lowest terms, or scale a recipe or mixture up and down while keeping the parts in balance.
• GPA Calculator - Calculate grade point average weighted by credit hours, on the 4.0 scale. Add your courses, see the GPA, and work out what you need next term.
• Tip Calculator - Calculate a tip at any percentage, split the total between any number of people, and round the per-person amount up or down to something payable.
• Discount Calculator - Find the sale price after one or more discounts, see how much you save, and work backwards from a sale price to the discount percentage.
• Aspect Ratio Calculator - Lock an aspect ratio and get the matching width or height. Includes 16:9, 4:3, 1:1, 21:9 and the common social and video presets.
• Loan Calculator - Calculate the monthly payment, total interest and payoff schedule for a mortgage, car loan or personal loan. See how extra payments shorten the term.
• Compound Interest Calculator - See how a lump sum and regular contributions grow with compound interest. Adjust the rate, term and compounding frequency and watch the breakdown.
• VAT & Sales Tax Calculator - Add VAT or sales tax to a net price, or strip it out of a gross price to find the net amount and the tax. Includes common European VAT rates.
• Rent vs Buy Calculator - Compare renting against buying over any horizon, including the investment return on the deposit you would not have tied up. Finds the break-even year.
• Debt Payoff Calculator - Plan your way out of multiple debts. Compare the avalanche and snowball methods side by side and see what an extra payment each month actually saves.
• Retirement Calculator - Project your savings to retirement and through it. See what the pot becomes, what income it sustains, and whether it runs out before you do.
• Car Loan Calculator - Calculate a car loan payment including trade-in, deposit and sales tax. See the total interest and how much of the price you are financing.
• Investment Return Calculator - Calculate compound annual growth rate and total return from a start and end value, and see how long a given rate takes to double your money.
• Profit Margin Calculator - Calculate profit margin and markup from cost and price, set a price from a target margin, and find the units needed to break even.
• Mortgage Affordability Calculator - Work out the mortgage a lender would actually offer you, from your income, debts and deposit, using the 28/36 debt-to-income rules lenders apply.
• Salary Calculator - Convert pay between hourly, daily, weekly, monthly and annual. Adjust hours and working weeks to compare a contract rate against a salary properly.
• Savings Calculator - Find out what regular monthly saving grows into, or how much you need to put aside each month to hit a target by a given date.
• Currency Converter - Convert between more than 150 currencies at current exchange rates. Swap direction in one click and see the rate used for the conversion.
• Elasticity Calculator - Calculate price elasticity of demand, income elasticity and cross elasticity using the midpoint method, with a plain reading of what each result means.
• P-Value Calculator - Calculate a p-value from a z-score or from an observed value, mean and standard deviation. Supports one- and two-tailed tests with an interpretation.
• Standard Deviation Calculator - Paste a list of numbers to get the mean, median, mode, range, variance and standard deviation, for both a sample and a whole population.
• Linear Regression Calculator - Fit a least-squares regression line to paired data. Get the slope, intercept, R-squared, correlation and a scatter plot with the fitted line.
• Chi-Square Calculator - Run a chi-square test on a contingency table or against expected frequencies. Get the statistic, degrees of freedom, p-value and an interpretation.
• BMI Calculator - Calculate body mass index from height and weight in metric or imperial units, see your category, and the weight range for a BMI of 18.5 to 25.
• Sleep Calculator - Find the bedtime or wake time that lets you finish a full sleep cycle, so you wake in light sleep rather than being pulled out of deep sleep.
• Calorie Calculator - Estimate your daily calorie needs from height, weight, age and activity, with targets for losing or gaining weight and a macronutrient breakdown.
• Body Fat Calculator - Estimate body fat percentage from height, neck, waist and hip measurements using the US Navy formula, with lean mass and category comparison.
• Running Pace Calculator - Calculate running pace, finish time or distance from any two of the three, with split times and predicted times at other race distances.
• Random Number Generator - Generate random numbers in any range, with or without duplicates. Draw one number or a whole set, using your browser's cryptographic randomness.
• Coin Flip - Flip a virtual coin once or many times. See heads and tails counts, the running percentage and the full sequence of results.
• Dice Roller - Roll any number of dice with any number of sides. Supports standard tabletop dice, modifiers and advantage or disadvantage on a d20.
• Wheel of Fortune - Enter a list of names or options and spin the wheel to pick one at random. Ideal for classroom picks, prize draws and settling group decisions.
• Time Duration Calculator - Work out the hours and minutes between two times, including shifts crossing midnight, with breaks deducted and decimal hours for payroll.
• Age Calculator - Calculate exact age from a date of birth in years, months and days, plus total weeks, days and hours lived and the countdown to the next birthday.
• Date Difference Calculator - Count the days, weeks, months and years between two dates, with an option to count business days only and to add or subtract days from a date.
• Unix Timestamp Converter - Convert a Unix timestamp to a human-readable date and back. Handles seconds and milliseconds, UTC and local time, and ISO 8601 output.
• Time Zone Converter - Convert a time between any number of time zones at once and find the hours that work for everyone, with daylight saving handled automatically.
• Unit Converter - Convert length, weight, temperature, area, volume, speed, time and digital storage between metric and imperial units with full precision.
• Cooking Converter - Convert cups, spoons, grams, ounces and millilitres for real ingredients. Flour and honey weigh very differently per cup, and this accounts for that.
• Roman Numeral Converter - Convert numbers to Roman numerals and Roman numerals to numbers, from 1 to 3999, with a breakdown showing how each numeral is built.
• Color Converter - Convert colors between HEX, RGB, HSL, HSV and CSS names. Includes a live preview, contrast checking and shade and tint generation.
• Word & Character Counter - Count words, characters with and without spaces, sentences and paragraphs, estimate reading time, and transform text case as you type.
• Text Compare - Compare two texts side by side and see exactly which lines were added, removed or changed, with the option to ignore case and whitespace.
• Lorem Ipsum Generator - Generate lorem ipsum placeholder text by paragraphs, sentences, words or characters, as plain text or wrapped in HTML tags.
• Base64 Encoder / Decoder - Encode text to Base64 and decode Base64 back to text, with full Unicode support and a URL-safe variant. Runs entirely in your browser.
• URL Encoder / Decoder - Percent-encode and decode URLs and query strings, with separate handling for full URLs and individual components. Includes a query string parser.
• JSON Formatter - Format, validate and minify JSON with clear error messages that point at the line and column. Sort keys and escape or unescape strings.
• UUID Generator - Generate cryptographically random version 4 UUIDs, one or thousands at a time, in uppercase, lowercase, braced or plain formats.
• Hash Generator - Generate SHA-1, SHA-256, SHA-384 and SHA-512 hashes of any text using the Web Crypto API. Runs locally, nothing is uploaded.
• Password Generator - Generate strong random passwords or memorable passphrases with adjustable length and character sets, plus an entropy-based strength estimate.
• JWT Decoder - Decode a JSON Web Token to read its header, claims and expiry. Runs entirely in your browser, so tokens are never transmitted.
• Regex Tester - Test a regular expression against sample text with live highlighting, capture groups, named groups and a plain-language explanation of errors.
• Number Base Converter - Convert numbers between binary, octal, decimal, hexadecimal and any base from 2 to 36, with the bit pattern shown alongside the result.
• What's My IP - See your public IP address along with its approximate location, internet provider and the details your browser reveals to every site you visit.