Litre

The litre (American: liter) is a unit of volume measurement, equal to 1 dm³, or 0.001 m³. The litre was originally intended as a unit of fluid and bulk dry measure, and is slightly larger than the American quart (and slightly smaller than an imperial quart.)

The kilogram was originally defined as the weight of one litre of pure water at the freezing point.

Other units

The U.S. quart is exactly 0.946 352 946 litre. The U.S. gallon is exactly 3.785 411 784 litres. The Imperial quart is exactly 1.136 522 5 litres. The Imperial gallon is exactly 4.546 09 litres. The acre-foot is about 1 233 482 litres.