US, UK and Metric Kitchen Measures Converter

Convert every common kitchen volume measure between US customary, imperial, metric and Australian conventions, in any direction, with each unit’s system named: a US pint is 473 mL and an imperial pint 568 mL, and an Australian tablespoon is 20 mL against 15 mL everywhere else.

Two definitions; everything else is arithmetic

The five that catch people out

Every common kitchen volume measure, and which system it belongs to

Pints, ounces, spoons and six different cups

A pint is not a pint. The imperial pint is 568.26 millilitres and the US liquid pint is 473.18 — the imperial one is 20.1% larger. Both are exact, because both systems are defined against the metre: the US gallon is 231 cubic inches of 25.4 mm each, and the imperial gallon is 4.546 09 litres. Everything on this page is computed from those two definitions.

The fluid ounce runs the other way. This is the trap inside the trap. The imperial pint is larger than the US pint, but the imperial fluid ounce is smaller than the US one: 28.413 mL against 29.574 mL. The reason is that an imperial pint is twenty imperial fluid ounces while a US pint is sixteen US ones. Convert a British recipe by assuming its ounces are yours and you are out by 4.1% — and in the direction you did not expect.

The Australian tablespoon is 20 millilitres. Everywhere else a tablespoon is 15 mL and equals three teaspoons; in Australia it is 20 mL and equals four. This is a genuine and unusually dangerous trap, because it lands on exactly the ingredients where a third too much matters: baking powder, bicarbonate of soda, salt, strong spices, gelatine. An ANZ recipe asking for two tablespoons of baking powder means 40 mL, and a British cook reading it will add 30.

There are six cups. The US customary cup is 236.59 mL, half a US pint. The metric cup used in Australia, New Zealand, Canada and South Africa is 250 mL. US nutrition labels use a 240 mL legal cup defined in 21 CFR 101.9. Older Canadian recipes use 8 imperial fluid ounces, 227.30 mL. Japanese recipes use 200 mL. And the “imperial cup” — which is worth saying plainly — is not a unit anybody ever legislated. British recipes have been written in grams and millilitres since the 1970s. Where a chart quotes an imperial cup it usually means half an imperial pint, 284.13 mL, but 6 and 8 imperial fluid ounces are both in print, and the difference between them is 67%. If a recipe says cup without saying whose, that is a question to answer before you start, not a number to look up.

What this page is for. A search engine will convert a millilitre to a fluid ounce. What it will not do is tell you which fluid ounce the recipe meant, and that is the entire difficulty. The table below gives every unit with the system it belongs to, so you can start from the right one. For the ingredients themselves, the cups to grams converter turns a cup of a named ingredient into grams; the oven temperature converter deals with the gas mark at the top of the same recipe; and the butter converter handles the sticks, which are a mass measure wearing a volume’s name.

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References

1. National Institute of Standards and Technology. NIST Handbook 44 (2026 edition), Appendix C, General Tables of Units of Measurement. The US liquid gallon is 231 cubic inches exactly and the British imperial gallon is 4.546 09 L exactly; every volume on this page is derived from those two definitions and the exact inch.
2. Code of Federal Regulations, 21 CFR 101.9(b)(5)(viii): the cup used in US nutrition labelling is 240 mL and the tablespoon 15 mL, neither of which is the US customary unit of the same name.
3. Tablespoon and Cooking weights and measures (encyclopaedia articles), used for the metric kitchen conventions and for the Australian 20 mL tablespoon, which they state as the Australian official definition. A primary Australian government source for the 20 mL tablespoon could not be retrieved while this page was written, so the figure is cited here rather than to a standard; it was checked numerically against the statement that an Australian tablespoon is four teaspoons of 5 mL, which is consistent.
4. Cup (unit) (encyclopaedia article), for the US legal, metric, Canadian and Japanese cups and for the point that the imperial cup is not a legally defined unit; the 6 imperial fluid ounce figure it gives is traced there to Enquire Within Upon Everything (1894).
5. The international avoirdupois pound and the international inch were fixed in 1959 by agreement between the national standards laboratories of the United States and the Commonwealth: 1 lb = 0.453 592 37 kg and 1 in = 25.4 mm, both exactly.