Cooking converter
Convert between kitchen volumes. There are five different cups and three different tablespoons, and this page tells you which one it used. Nothing you type here leaves your browser — it is worked out on your own device, so there is nothing to send and nothing to log.
There are five cups
Not five names for one thing — five different volumes, all called a cup, spanning eighty-four millilitres from smallest to largest. Every converter on the internet picks one and does not say which.
| US customary | 236.59 ml — one sixteenth of a US gallon. What American recipes mean. |
|---|---|
| US nutrition label | 240 ml exactly, fixed by US food labelling law. 1.4% off the recipe cup, which is close enough that nobody notices packaging and recipes disagreeing. |
| Metric | 250 ml exactly. Australia, New Zealand, Canada. 5.7% bigger than the US cup — about seven grams on a cup of flour. |
| Imperial | 284.13 ml — ten imperial fluid ounces. Old British recipes, and 20% bigger than the US cup. |
| Japanese | 200 ml exactly, from the gō. |
And the Australian tablespoon is a third bigger
A tablespoon is 15 millilitres almost everywhere, and 20 in Australia. That is four teaspoons rather than three. A recipe written in Sydney and cooked in Sheffield gets a third less of everything measured in tablespoons — which, for baking powder or yeast, is the difference between a rise and a brick.
The United States has its own quiet variation: a US tablespoon is half a US fluid ounce, which is 14.79 ml rather than 15. That one is small enough not to matter, and it is shown anyway, because the point of this page is that you can see which number was used.
The imperial fluid ounce is smaller and the imperial pint is bigger
Which sounds like a mistake and is not. A US pint is sixteen fluid ounces; an imperial pint is twenty. So the imperial ounce is 4% smaller than the US one, and the imperial pint is still 20% larger. Anybody converting a drink recipe between the two and checking only one of the numbers will get it wrong.
Where these numbers come from
They are exact, and they are derived here rather than copied from another table. The US gallon is exactly 231 cubic inches and the inch is exactly 25.4 mm, so the US fluid ounce is exactly 29.5735295625 ml and the cup, the tablespoon and the teaspoon are halves and sixteenths and sixths of that. The imperial gallon has been exactly 4.54609 litres since 1985. Nothing here is measured, so nothing here is uncertain.
What it will not do
- It will not turn volume into weight. That needs a density, which is a property of the ingredient rather than of the units — see the cups to grams page, which says where its densities came from.
- It will not guess which cup your recipe meant. If it does not say, the safe bet is the US customary cup for American recipes and the metric cup for Australian ones; British recipes mostly weigh things, which is why British baking books travel better.
- It will not correct for a badly filled spoon. A heaped teaspoon is roughly twice a level one, and no arithmetic can find that out.