Unit converter guide and definitions
Select a category, enter a value and choose the input and output units. Nearby units appear first; expand the list to see every unit. Temperature and temperature intervals are separate categories.
Unit definitions
1 in = 25.4 mm, 1 lb = 0.45359237 kg, and standard gravity g₀ = 9.80665 m/s².
International inch and pound, standard gravity, US liquid and imperial gallons, pound mass and pound-force, metric and mechanical horsepower are distinguished. Calories are thermochemical; BTU uses IT. Manometer columns use conventional values. Tsubo is customary; acre uses the international foot. Binary and decimal prefixes differ.
Calculation and displayed precision
Conversion runs in your browser. Results are rounded and subject to floating-point arithmetic. Check original definitions and required precision for important use. This is not a legal metrology certification service.
Input tips
Similar unit names may have different definitions. Check the category notes and the full name of each selected unit.