Convert pt to ml

A US pint is 473 ml and an imperial pint is 568 ml — a fifth larger. This is the single most consequential difference between the two systems for anybody following a recipe or ordering a drink.

A millilitre is exactly one cubic centimetre, which is why medicine and laboratory work quote both and mean the same thing.

The factor is 473.176473, and almost nobody carries that around. Rounded to 470 it is off by 0.67 % — which stays invisible on small numbers and turns into a whole unit somewhere around 1,000 pt.

That is the number worth knowing before you round: not the error itself, but where it stops being ignorable. Below that point the shorter factor is the sensible one; above it, use the field above, which never rounds until it prints.

The US pint is two different sizes wearing one name. This page uses the US one, which is 473.17647 ml; the imperial one still used in the UK and Ireland is 568.26125 ml — larger by 20.1 %.

That gap is the awkward size: far too big to ignore in a recipe, and far too small to spot from the answer alone. If your figure came from a British source, take the second number, and note that the fluid ounce is the one unit here where the imperial measure is the smaller of the two.

One US pint is 473.18 ml, two are 946.35, a half is 236.59 and a quarter is 118.29. The single most useful thing about those numbers is that none of them is a graduation on anything: a domestic jug is marked at 50 ml with 25 ml subdivisions, so a pint has to be read as most of the way between 450 and 500.

That makes 475 ml the working figure for a single pour. It is 1.8 ml over, which is four tenths of a per cent and far below what the jug can show, and it is a number that can be read off the scale rather than estimated between two lines. Precision here belongs to the arithmetic, not to the pouring.

Pints turn up in American recipes for the ingredients that are sold in them: cream, stock, buttermilk, half-and-half, ice cream and berries. In every one of those cases the pint is the package, and the recipe means "one of those containers" as much as it means a volume.

That matters for substitution. A pint of cream is 473 ml, and the metric carton nearest it is 500 ml, so a recipe calling for a pint and a half wants 710 ml where the shop sells 1,000 in two cartons. Working out the total in millilitres before shopping is what stops a recipe from generating an awkward remainder in the fridge.

An imperial pint is 568.26125 ml and a US pint is 473.176473 ml. The gap is 95.08 ml, which is 20.1 per cent of the American measure, and it exists because Britain redefined its gallon in 1824 while the United States kept an older English wine gallon of 231 cubic inches. Both divide the gallon into eight, so the pint inherits the whole difference.

A recipe is the place this costs something. A pint of stock read as imperial when it was American adds 95 ml to a sauce, and read as American when it was British takes the same amount out. Neither error announces itself while cooking, and both are large enough to be tasted at the end, which is why the origin of a recipe is worth establishing before the first pint is poured.

The metric package nearest a US pint is 500 ml, and it holds 26.8 ml more — 5.7 per cent. For stock, milk, buttermilk or anything going into a pan with other liquids, tipping in the whole carton is the right answer and the difference is beneath notice.

The exceptions are the recipes where the liquid is a ratio rather than an ingredient: custards, panna cotta, batters, anything set with gelatine or thickened with a fixed amount of starch. There the extra 27 ml is a change to the formula, and measuring 473 ml out of the carton takes ten seconds and removes the question.

The American mnemonic is that a pint’s a pound the world around, and it very nearly works: 473 ml of water weighs 473 g, which is 1.043 pounds. The four per cent error is inside what the rhyme was ever meant to carry, and it makes the US pint a usable rough weight for anything water-like.

It is not true anywhere the pint is imperial. A British pint of water weighs 568 g, which is a pound and a quarter, and the British version of the saying says exactly that. So the rhyme is not folk wisdom that drifted — it is two accurate sayings about two different units, and only one of them has travelled.

A US pint is sixteen fluid ounces and two customary cups, exactly, because all three are divisions of the same 231-cubic-inch gallon. That is why an American recipe moves between them without comment, and why a quantity given in cups elsewhere in the same list is directly comparable without a second conversion.

It also explains the drinks aisle. A 16 fl oz can is a pint can and holds 473 ml; the 355 ml can beside it is 12 fl oz. Neither number was chosen to be round in metric, and both are round in ounces, which is a reliable way of telling which system designed a package before reading the label.

If the jug is coarse, build the pint out of smaller measures instead. Two cups is a pint, and a 250 ml metric cup twice gives 500 — over by 27. A 240 ml measure twice gives 480, over by 7. Four half-cups of 118.3 ml each is exact and slow. Which of those is right depends entirely on what the liquid is doing in the recipe.

For quantities under half a pint, spoons close the gap faster than the jug does. A tablespoon is 14.79 ml, so a quarter pint is 118.29 ml — eight tablespoons exactly, since a cup is sixteen. Building the awkward remainder out of whole tablespoons is more reliable than judging a jug between two lines.

Metric shelf labels give a unit price per litre, and a pint figure has to be scaled before it can be set against one. A pint is 0.473 litres, so a price per pint is a price per litre multiplied by 0.473 — or, going the useful way, a per-pint price divided by 0.473 to get the comparable figure. A product at £2 the pint is £4.23 the litre.

This is the arithmetic that makes an imported American product look cheaper than it is. A 473 ml container beside a 500 ml one at the same price is 5.7 per cent dearer per unit of contents, and neither label says so unless one of them carries the unit price. Converting to millilitres first and dividing the price by that is the comparison that holds regardless of what either package is called.