Unit Converter
Convert values between metric and imperial units across length, mass, temperature, area, volume, speed and digital storage.
About this tool
Pick a category, a from-unit and a to-unit, and the converted value updates as you type. Ten categories are covered: length, mass, temperature, area, volume, speed, data size, time, pressure and energy, each with the common SI and imperial/US units. Every category except temperature converts through a fixed base unit using exact factors (1 mile is 1609.344 m, 1 hour is 3600 s); temperature uses the real offset formulas, so 0 °C becomes 32 °F rather than 0. Everything runs in your browser.
When to use it
Questions
Why does the data category list both kB and KiB?
They are different. A kilobyte (kB) is 1000 bytes, the decimal unit drive makers and network speeds use; a kibibyte (KiB) is 1024 bytes, the binary unit operating systems use when they report file and memory sizes. The same distinction applies to MB vs MiB, GB vs GiB and TB vs TiB, and the gap grows at each step.
Why is temperature handled differently from the other categories?
Celsius, Fahrenheit and Kelvin scales have different zero points, so a single multiplier cannot convert them. The tool applies the proper formulas — Fahrenheit is (°C × 9/5) + 32, Kelvin is °C + 273.15 — which is why −40 °C and −40 °F come out equal.
How precise are the results?
Conversions use exact standard factors and are shown to about six significant figures, with trailing zeros trimmed and scientific notation for very large or very small values. The year unit is a flat 365 days.