| US Liquid pints (pt) | Milliliters (mL) |
|---|---|
| 1 US Liquid pint | 473.176473 mL |
| 2 US Liquid pints | 946.352946 mL |
| 3 US Liquid pints | 1419.529419 mL |
| 4 US Liquid pints | 1892.705892 mL |
| 5 US Liquid pints | 2365.882365 mL |
| 10 US Liquid pints | 4731.76473 mL |
| 20 US Liquid pints | 9463.52946 mL |
| 25 US Liquid pints | 11829.411825 mL |
| 50 US Liquid pints | 23658.82365 mL |
| 100 US Liquid pints | 47317.6473 mL |
| Reference | US Liquid pints (pt) | Milliliters (mL) |
|---|---|---|
| A teaspoon | 0.0105669 pt | 5 mL |
| A can of soft drink | 0.697414 pt | 330 mL |
| A wine bottle | 1.58503 pt | 750 mL |
| A bathtub | 317.006 pt | 150000 mL |
| An Olympic swimming pool | 5283441 pt | 2.5 × 109 mL |
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.
The millilitre is a unit of volume equal to one thousandth of a litre, written mL or ml. It is exactly one cubic centimetre. It is the working unit of medicine, cookery, cosmetics and the laboratory, and it is the smallest volume most people handle deliberately in the course of a day.
Medicine relies on it more heavily than on any other unit of volume. Oral liquids are dosed in millilitres, syringes are graduated in them, intravenous fluids are prescribed as so many millilitres per hour, and blood test results are reported per millilitre or per decilitre. The precision matters: a tenfold dosing error in a paediatric prescription is a difference of a single decimal place in this unit.
That is why the household spoon has been driven out of medical instructions. A teaspoon is nominally five millilitres, but real spoons vary from two to nine, so dosing devices are now supplied with liquid medicines and marked in millilitres. Regulators in several countries require the millilitre marking precisely because it removes an ambiguity that spoons cannot.
Cooking outside the United States runs on it. European and Asian recipes give liquids in millilitres and litres rather than in cups, which is more precise because a cup measures volume by an unstandardised container while a millilitre does not. Wine and spirit measures, coffee shot sizes, and the capacity of a baby bottle are all specified in millilitres.
A convenient identity helps in the kitchen and the laboratory alike. One millilitre of water has a mass of one gram, so a recipe or a protocol can move between mass and volume for water-like liquids without a real error. Cosmetics use the same unit throughout, from a five-millilitre sample to a five-hundred-millilitre bottle.
Against United States and imperial measures it converts awkwardly, and the two differ from each other. One millilitre is 0.0338 United States fluid ounces but 0.0352 imperial fluid ounces, so a fluid ounce is about four per cent larger in Britain than in America, and any drink or medicine volume converted between them needs to state which system was meant.
One millilitre equals 1 cubic centimetre, 0.001 litres, about 0.0338 US fluid ounces, or about 0.0352 imperial fluid ounces.