📐 Unit Converter

One number in, every unit at once: type an amount, pick the unit, and the whole table converts live. Eight categories, factors taken from the international definitions (1 inch = 2.54 cm exactly, 1 nautical mile = 1,852 m exactly, 1 lb = 0.45359237 kg by treaty since 1959), so the maths matches any official table. The conversion never leaves your device.

Click any row to make it the target unit. “Floz” = fluid ounce; US and UK pints/gallons differ — both are listed. Kilobyte (1,000) vs kibibyte (1,024) are both given because hard disks and RAM count differently on purpose.

The exactness is the point

Since 1983 the metre is defined by the distance light travels in 1/299,792,458 of a second, and every other length unit here is an exact multiple of it — no rounding in the factor table, only in the last digits of the answer (we show ten significant ones). Temperature is the odd one out: Celsius and Kelvin share a step size but different zeroes, and Fahrenheit is affine, not proportional — so it gets its own formulas instead of a factor.

Part of Everyday Tools — see also date & age, distances on Earth and the world clock.