From inches to kilometers, pints to liters, pounds per square inch to newtons and beyond, Wolfram|Alpha is the world's most extensive and accurate unit converter. Convert between thousands of common (and obscure) units of measurement drawn from a huge variety of different unit systems, including the US customary system, the metric SI system and many historical systems used throughout the world. As an added bonus, view comparisons to everyday unit scales, observe corresponding values when converted to related physical quantities, find physical quantities to which given units belong and get a feel for unit scales using graphical order of magnitude charts.
Calculate an exact unit conversion and obtain information about the physical quantities the unit measures, other related units and the unit system or systems to which the unit belongs.
Perform calculations with combinations of units, including with a desired output unit.
Find cooking measurement equivalents.
Convert a quantity (i.e. a unit with a magnitude) to other units and explore comparisons with specific objects and corresponding quantities.
Compare two or more units or, alternately, see common objects having similar unit dimensions and values.
Switch from SI units to others and uncover additional knowledge regarding those units.
Show a table of metric prefixes that may precede a basic unit of measurement and indicate a multiple (or fraction) of that unit.
Explore details about US customary units and change from US units to others.