US Gallon to Litre Conversion

1 gallon = 4 qt = 128 fl oz = 231 cubic inches = 3.785411784 litres
U.S. liquid gallon is defined as 231 cubic inches, and is equal to 3.785411784 litres (exactly) or about 0.13368 cubic feet. This is the most common definition of a US gallon.
A litre (US: liter) is defined as one cubic decimetre (1 L = 1 cubic dm). Hence 1 L = 0.001 cubic m. The word "litre" came from an older French unit, the litron, the name came from Greek via Latin. The metric system used litre as a volume unit.