Free Unit & Number Converters
Convert between metric and imperial units, temperatures, data sizes and time, write numbers as words and translate between Roman numerals and digits. Each converter also shows a full table of equivalent units.
10 converters tools
Number to Words Converter
Write numbers in words, useful for cheques and legal documents.
XIVRoman Numeral Converter
Convert numbers to Roman numerals and back.
m↔ftLength Converter
Convert between miles, kilometres, feet, inches, metres and more.
kg↔lbWeight Converter
Convert kilograms, pounds, stone, ounces and grams.
°CTemperature Converter
Convert Celsius, Fahrenheit and Kelvin.
LVolume Converter
Convert litres, UK and US gallons, pints, cups and millilitres.
mphSpeed Converter
Convert mph, km/h, m/s and knots.
m²Area Converter
Convert square metres, square feet, acres and hectares.
GBData Storage Converter
Convert bytes, KB, MB, GB and TB.
sTime Unit Converter
Convert seconds, minutes, hours, days, weeks and years.
Frequently asked questions
Which gallon do you use?
The volume converter includes both UK (imperial) and US gallons, clearly labelled.
Are conversions exact?
Factors are defined by international standards, and results are shown to as many decimal places as are useful.