One litre is the volume of one cubic decimetre, that is a cube of 10 x 10 x 10 centimetre. One litre of water has the mass of exactly one kilogram. This results from the definition given in 1795, where the gram was defined as the weight of one cubic centimeter of melting ice.
The capital letter "L" is preferred by some people as the small "l" can look like the number one "1".
- 1 imperial gallon = 4.5461 litres
- 1 U.S. gallon = 3.7854 litres
- 1 litre = 1 dm3
The litre is a metric unit, but not an SI unit. The official unit for volume is the cubic metre. Nevertheless, the litre is accepted for use in the SI system. The litre is among the units that are widely used, both in everyday life, and in scientific texts. "The hectare, the litre and the tonne are different from the respective (..) SI units only by a (..) power of ten." "Their use is expected to continue indefinitely, and each has an exact definition in terms of an SI unit."
- "Decree on weights and measures". 7 April 1795. http://smdsi.quartier-rural.org/histoire/18germ_3.htm. "Gramme, le poids absolu d'un volume d'eau pure égal au cube de la centième partie du mètre , et à la température de la glace fondante." English translation: "Gramme: the absolute weight of a volume of pure water equal to the cube of the hundredth part of the meter, at the temperature of melting ice."
- International Bureau of Weights and Measures (2006), The International System of Units (SI) (8th ed.), p. 124, ISBN 92-822-2213-6, http://www.bipm.org/utils/common/pdf/si_brochure_8_en.pdf