US Liquid pint (pt)

The United States liquid pint is a unit of volume equal to exactly 473.176473 millilitres. Its symbol is pt. It is sixteen United States fluid ounces and an eighth of a United States gallon. It is noticeably smaller than the imperial pint of 568 millilitres, because the American pint holds sixteen fluid ounces where the British one holds twenty.

That difference of four ounces is the whole story of the two pints. Both systems descend from the same medieval English measures, but Britain rebuilt its liquid chain in 1824 around a gallon of ten pounds of water, while the United States kept the older wine gallon of 231 cubic inches. The pint inherited the difference, and a British pint is now about a fifth larger than an American one.

The rhyme survives because the American pint fits it. A pint's a pound the world around works for the United States pint, since sixteen fluid ounces of water weigh 1.04 pounds, and it fails in Britain, where a pint of water weighs a pound and a quarter. The saying is a useful reminder that measurement rhymes travel worse than the measurements themselves.

Draught beer is where the difference becomes visible to travellers, and where American practice is looser than British. There is no federal requirement that a glass sold as a pint contain a pint, and the widely used sixteen-ounce shaker glass holds that volume only when filled to the brim, so a poured beer with a head contains less. Several states have legislated on the point precisely because the imperial system's verified glass has no American equivalent.

Domestic packaging uses it constantly. Milk, cream, ice cream and soft fruit are sold in pint containers, and a donated unit of blood is loosely called a pint although it is about 470 millilitres. Premium ice cream in a pint tub is one of the most recognisable retail formats in the country.

A separate United States dry pint of 551 millilitres exists for produce, and nothing in the word distinguishes it. A pint of cream and a pint of blueberries are therefore different quantities, differing by about sixteen per cent, which is the sort of detail that only becomes visible when someone tries to convert a recipe.

One United States liquid pint equals 473.176 millilitres, 16 US fluid ounces, 0.125 US gallons, or about 0.833 imperial pints.

US Liquid pint conversion table