All calculators and converters
Type a word such as “cups”, “weeks” or “discount” to narrow the list, or browse by collection.
Unit converters
- Length converterCentimeters, inches, feet, meters, kilometers, miles and nautical miles, with the factor shown.
- Weight converterGrams, kilograms, ounces, pounds, stone, tonnes and US or long tons, using the exact pound.
- Volume converterLiters, cubic units and both gallon systems, including the 16 and 20 fl oz pints.
- Temperature converterCelsius, Fahrenheit, kelvin and Rankine, with the formula shown for every pair.
- Area converterSquare meters, square feet, acres, hectares and square miles, with the squared factor explained.
- Speed converterkm/h, mph, m/s, knots and ft/s, with road, wind and boating examples.
- Cooking measurement converterUS, label, metric and Japanese cups, plus US, metric and Australian spoons, in milliliters.
- Pressure converterpsi, bar, kPa, atm, hPa, kgf/cm², mmHg and inHg for tires, weather maps and gauges.
- Data storage converterDecimal kB, MB, GB, TB and binary KiB, MiB, GiB, TiB, plus bits for network speeds.
- Fuel economy converterUS mpg, UK mpg, L/100 km and km/L, with the reciprocal explained and a ready table.
Percentage calculators
- Percentage calculatorFind P% of X, what percent A is of B, or the whole when you know a part and its percent.
- Percent change calculatorPercent increase or decrease from an old value to a new one, plus raising or lowering a number by a percent.
- Percent difference calculatorCompare two values by the gap relative to their average, with percent change in both directions alongside.
- Discount calculatorFinal price, savings and the effective discount for one or two stacked percentages, or the percent off from two prices.
- Reverse percentage calculatorRecover a net price, an earlier salary or a regular price from the value after a percentage was added or removed.
Date and time calculators
- Days between datesDays, weeks, months and weekdays between two dates, counted with or without the end date.
- Age calculatorExact age in years, months and days, totals lived, the weekday of birth and a next-birthday countdown.
- Date calculatorAdd or subtract years, months, weeks and days from a date and see which weekday it lands on.
- Time zone converterConvert a date and time between world time zones, with UTC offsets and daylight saving warnings.
- Time duration calculatorHours and minutes between two clock times, minus breaks, in decimal hours too, plus a running total.
- Week number calculatorISO week number, week-year and Monday-to-Sunday dates for any date, plus the reverse lookup.
- Business days calculatorWorking days between two dates minus your own holidays, or a date plus a number of working days.
Everyday math
- Fraction calculatorAdd, subtract, multiply and divide fractions and mixed numbers, simplified, with the working.
- Decimal to fraction converterDecimals to simplest fractions (repeating ones too), fractions to decimals, and the nearest 1/16 or 1/32.
- Ratio calculatorSimplify A:B or A:B:C, solve a proportion for x, or share a total in a ratio.
- Average calculatorMean, median, mode, range, count and sum of a pasted list, plus a weighted mean.
- Rounding calculatorRound to decimal places, significant figures or a multiple, with seven rounding modes.
- GCF and LCM calculatorGreatest common factor, least common multiple and prime factors of a list of whole numbers.
- Roman numeral converterNumbers to Roman numerals and back, with a breakdown and a standard-form check.
Practical calculators
- Tip calculatorTip amount, total and each person's share, with an option to tip on the subtotal and round shares up.
- Unit price calculatorPrice per kg, liter or item for up to three packages, with the cheapest marked and the others' gap in percent.
- Fuel cost calculatorFuel needed and cost for a drive, in metric or US and UK units, shared between the people in the car.
- Gas mileage calculatorYour car's measured fuel economy from one full tank to the next, in L/100 km, km/L and US and UK mpg.
- Electricity cost calculatorEnergy use in kWh and running cost of any appliance per day, for a chosen number of days and per year.
- Recipe scalerMultiply every ingredient by the right factor for more or fewer servings, with friendly fractions for cups and spoons.
- Speed, distance and time calculatorFind speed, distance or time from the other two, in km or miles, with running or cycling pace.