About

UnitNerd is a small, independent unit converter for people who care whether a pint is 568 ml or 473 ml. Exact defined values, no rounding surprises, no clutter.

How we calculate

Every unit is defined against a single base unit for its category using the exact factor set by international agreement — for example, an inch is exactly 0.0254 metres and a pound is exactly 0.45359237 kilograms. Results are calculated in your browser at full double precision and only rounded for display.

Where a conversion isn't a plain multiplication — temperature scales with different zero points, or fuel economy where miles per gallon is the inverse of litres per 100 km — we use and show the exact formula.

UK and US units

Imperial (UK) and US customary units share names but not sizes. A UK gallon is 4.54609 litres while a US gallon is 3.785411784 litres, so we always label them separately to avoid mix-ups.

Why it's free

The site may show a small number of ads to cover hosting. Ads are never placed above the converter, and no ad scripts load until you consent.