Units and Conversions

Convert a number between bases 2 to 36 exactly (binary, octal, decimal, hex), with big-integer precision.

Convert cooking measures: cups, tablespoons, teaspoons, ml, ounces and grams, with weight for flour, sugar, butter and more.

Convert data sizes between bytes, KB/MB/GB/TB (decimal) and KiB/MiB/GiB/TiB (binary), and the time to transfer at a speed.

Turn seconds into a readable duration (2 h 5 min) or parse one like '1d 3h 20m' back into seconds, minutes and hours.

Apparent temperature: heat index from temperature and humidity, wind chill from temperature and wind, with a danger category.

Convert fuel economy between US mpg, UK mpg, km per litre and litres per 100 km, with optional trip fuel and cost.

Write a whole number in English words (cardinal and ordinal) and as a check-writing amount in dollars and cents.

Convert between integers (1-3999) and Roman numerals, and check whether a Roman numeral is written in canonical form.

Convert a value between units of length, mass, volume, area, speed, pressure, energy, power, time or temperature, exactly.