The mass of one liter liquid water is almost exactly one kilogram.
It is equal to 1 cubic decimeter (dm3), 1,000 cubic centimeters (cm3) or 1/1,000 cubic meter. The liter (also written 'litre' SI symbol L or l) is a non-SI metric system unit of volume. There are three definitions in current use: the imperial gallon (≈ 4.546 L) which is used in the United Kingdom and semi-officially within Canada, the United States (liquid) gallon (≈ 3.79 L) which is the commonly used, and the lesser used US dry gallon (≈ 4.40 L). The gallon (abbreviation 'gal'), is a unit of volume which refers to the United States liquid gallon.
Let's see how both units in this conversion are defined, in this case Gallons and Liters: Gallon (gal)
