Sorry, I meant millilitres, not millimetres.

Come on, Americans don't do metric, I know one gallon is four quarts though, and a quart is 32 ounces. You'll have to call upon your Europeans for this one, or maybe a good old Canadian.

1) Current use: "There are three definitions in current use: U.S. liquid gallon is legally defined as 231 cubic inches, and is equal to 3.785411784 litres (exactly) or about 0.13368 cubic foot. This is the most common definition of a gallon. The U.S. fluid ounce is defined as 1/128 of a U.S. gallon. U.S. dry gallon is one-eighth of a U.S. Winchester bushel of 2150.42 cubic inches, thus 268.8025 cubic inches (exactly) or 4.40488377086 litres (exactly) Imperial (UK) gallon is legally defined as 4.54609 litres (~277.42 cu in), which is about 1.2 U.S. liquid gallons. This definition is used in the United Kingdom, and is based on the volume of 10 pounds of water at 62 °F. (A U.S. liquid gallon weighs about 8.33 pounds at the same temperature.) The Imperial fluid ounce is defined as 1/160 of an Imperial gallon. The Imperial gallon is no longer legal, in the UK, for trade or public administration purposes, but it is used colloquially (and in advertising) for fuel consumption figures in miles per gallon. The Imperial gallon continues to be used as a unit of measure for fuel in various countries (for example, United Arab Emirates and Sierra Leone). The word has also been used as translation for several foreign units of the same magnitude.[citation needed] The U.S. dry gallon is less commonly used. The gallons in current use are subdivided into eight pints or four quarts. The liquid gallons are also subdivided into 32 gills." Source: http://en.wikipedia.org/wiki/Gallon This article mentions also historical uses of the gallon, for instance: "The corn or dry gallon was used in the United States until recently for grain and other dry commodities. It is one eighth of the (Winchester) bushel, originally a cylindrical measure of 18½ inches in diameter and 8 inches depth. That made the dry gallon 9¼²·π in³ ≈ 268.80252 cubic inches. The bushel, which like dry quart and pint still sees some use, was later defined to be 2150.42 cubic inches exactly, making its gallon 268.8025 cubic inches exactly (4.40488377086 L). In previous centuries there had been a corn gallon of around 271 to 272 cubic inches." "The wine, fluid, or liquid gallon is the standard U.S. gallon since the early 19th century. The wine gallon, which some sources relate to the volume occupied by eight medieval merchant pounds of wine, was at one time defined as the volume of a cylinder six inches deep and seven inches in diameter, i.e. 6·3½²·π = 230.90706 cubic inches. It had been redefined during the reign of Queen Anne, in 1706, as 231 cubic inches exactly (3 in × 7 in × 11 in), which is the result of the earlier definition with π approximated to 22⁄7. Although the wine gallon had been used for centuries for import duty purposes there was no legal standard of it in the Exchequer and a smaller gallon (224 cu in) was actually in use, so this statute became necessary. It remains the U.S. definition today." and a lot more... Incidentally, if you want to convert liter in millilitre, you should use following formula: 1 litre = 1.000 millilitres.