Unit Converter Center

The world runs on more than one system of measurement at once. Science and most countries use the metric system (SI); the United States keeps its own customary units; and older trades still carry historical ones. Moving a number from one to another should be quick, exact, and clear about which system you are in.

Pick a category, type a value, and choose the units to convert from and to. The result updates as you type, and a full table shows the same value expressed in every unit of that category.

Linear conversions (length, weight, volume and the like) are exact to the defining constants. Temperature is handled through Kelvin because its scales have offsets, so it is marked as an offset scale rather than a simple ratio.