How it works
- Most categories convert through a fixed multiplier against an SI base unit (metres, kilograms, seconds, pascals, joules, watts…), so results are exact to full floating-point precision.
- Temperature and fuel economy are non-linear, so they use the correct formulas (Celsius/Fahrenheit/Kelvin, and reciprocal MPG↔L/100km) rather than a straight multiplier.
- All conversions happen instantly in your browser as you type.
Convert between metric and imperial units across 17 categories — length, weight, temperature, area, volume, time, speed, angle, force, pressure, energy, power, frequency, digital storage, data rate, fuel economy and cooking measures — instantly and entirely in your browser. Nothing is uploaded, so it works offline once loaded.
Frequently asked questions
Are the conversions exact?
Length, weight, area, volume and data conversions use exact, internationally-defined multipliers against an SI base unit, so results are precise to full floating-point accuracy. Temperature uses the exact Celsius/Fahrenheit/Kelvin formulas rather than a linear approximation.
Why is 1 KiB shown as 1.024 KB?
Because KB (kilobyte) is 1,000 bytes while KiB (kibibyte) is 1,024 bytes. The converter keeps the decimal (KB, MB, GB) and binary (KiB, MiB, GiB) families separate so you always know which standard you're using.
Does it handle fuel economy both ways?
Yes — it converts between miles-per-gallon (US and UK) and litres-per-100km, which are inverse scales, so the maths is done correctly rather than treated as a straight multiplier.
Is my data sent anywhere?
No. Every calculation runs in JavaScript on your device. There is no server call, so you can use it with sensitive numbers and even offline after the first visit.