There are 236.6 ml in a US cup, and 250 ml in a metric cup. Both answers are correct, and which one you need depends on which cup the recipe means. An American cup holds 236.59 ml, which is usually rounded to 237 ml or 240 ml in a recipe. A metric cup, used in Australia and in many international recipes, holds exactly 250 ml. The difference is about 13 ml, or 5 percent, which does not matter in a soup and can matter in a cake. This page gives you both tables, real examples, and the trick for knowing which cup you are holding.
The conversion table
| Cups | US millilitres | Metric millilitres | US fluid ounces |
|---|---|---|---|
| 1/4 cup | 59.1 ml | 62.5 ml | 2 fl oz |
| 1/3 cup | 78.9 ml | 83.3 ml | 2 2/3 fl oz |
| 1/2 cup | 118.3 ml | 125 ml | 4 fl oz |
| 2/3 cup | 157.7 ml | 166.7 ml | 5 1/3 fl oz |
| 3/4 cup | 177.4 ml | 187.5 ml | 6 fl oz |
| 1 cup | 236.6 ml | 250 ml | 8 fl oz |
| 1 1/2 cups | 354.9 ml | 375 ml | 12 fl oz |
| 2 cups | 473.2 ml | 500 ml | 16 fl oz |
| 3 cups | 709.8 ml | 750 ml | 24 fl oz |
| 4 cups | 946.4 ml | 1,000 ml | 32 fl oz |
The US column is rounded to one decimal place. The metric column is exact, because a metric cup is defined as 250 ml.
Worked example 1: a European recipe in an American kitchen
A German recipe calls for 250 ml of milk, and your measuring jug is marked in US cups. Two hundred and fifty millilitres is 1.06 US cups, so measure 1 cup plus about 1 tablespoon. For a soup, just measure 1 cup and add a splash — the difference of a tablespoon will not matter. For a custard, measure the extra tablespoon, because a custard that is short on milk will set too firmly. If your jug is marked in millilitres, the job is easier: measure 250 ml and ignore the cups entirely, because millilitres are the same everywhere.
Worked example 2: an American recipe and a metric jug
An American recipe calls for 1 cup of cream, and your jug is marked only in millilitres. One US cup is 236.6 ml, so measure 237 ml. If you measure 250 ml instead, you have added an extra 13 ml, which is about a tablespoon, and in a sauce that will not matter, but in a cake it can make the batter slightly wetter than the recipe intends. The practical rule is to round to the nearest 10 ml for cooking and to the nearest millilitre for baking, and to remember that 240 ml is the figure most American recipes use when they give a metric equivalent, because it is a round number that is close enough.
Worked example 3: a large batch, converted to litres
A punch recipe calls for 4 cups of juice, and you want to know how many litres that is for a dispenser marked in litres. Four US cups is 946.4 ml, which is just short of a litre, so you need a 1-litre bottle and you will have about 54 ml left over. If the recipe were written in metric cups, 4 cups would be exactly 1 litre. That is the kind of small difference that catches people out: 4 US cups is not a litre, it is 95 percent of a litre, and in a large batch the gap grows — 8 US cups is 1.89 litres, not 2 litres.
Method and source
A US cup is defined as 8 US fluid ounces, and a US fluid ounce is defined as 29.5735 millilitres, so a US cup is 236.588 millilitres, usually rounded to 236.6 ml. A metric cup is defined as exactly 250 millilitres. The two cups exist because the United States kept its customary system while Australia and other countries adopted a metric cup alongside the litre. The difference is 13.4 ml, or about 5.7 percent. In practice, most American recipes that give a metric equivalent use 240 ml for a cup, which is a round number between the two, and that is close enough for cooking. For baking, weigh the ingredients instead: a cup of flour can weigh anywhere from 120 to 142 grams depending on how you scoop it, so no volume conversion can be as accurate as a scale.
Practical guidance
The first thing to check is which cup the recipe means. If the recipe is American, its cup is 237 ml. If it is Australian or international, its cup is often 250 ml. If the recipe gives millilitres, use those directly and skip the cups. Buy a jug marked in both cups and millilitres, and use it for liquids; for dry ingredients, weigh them. When you scale a recipe, convert to millilitres first, do the multiplication, and convert back at the end, because millilitres are the smallest unit and the maths stays exact. And remember the anchor: 250 ml is a metric cup, 237 ml is a US cup, and 240 ml is the round number that most recipes use when they do not want to be precise.
Frequently asked questions
How many millilitres are in 1 cup?
There are 236.6 ml in 1 US cup, and 250 ml in 1 metric cup. Use 237 ml if your cups are American, and 250 ml if your cups are metric. The difference is about a tablespoon.
How many millilitres are in half a cup?
There are 118.3 ml in half a US cup, and 125 ml in half a metric cup. For most cooking, 120 ml is a good enough figure, but for baking, use the exact number for the cup you have.
How many cups are in 250 ml?
There is 1 metric cup in 250 ml, and about 1.06 US cups in 250 ml. If you are using American cups, measure 1 cup plus 1 tablespoon to get 250 ml.
Is 1 cup 250 ml?
Only if the cup is a metric cup. A US cup is 236.6 ml, which is 13.4 ml less than 250 ml. Many recipes round the US cup to 240 ml, which is close enough for cooking but not exact.
How many millilitres are in 2 cups?
There are 473.2 ml in 2 US cups, and 500 ml in 2 metric cups. Two US cups is just short of half a litre, by about 27 ml, which is roughly 2 tablespoons.
Should I measure liquids in cups or millilitres?
Millilitres, if your jug has them, because they are the same everywhere and they are more precise. Cups are convenient when a recipe is written in cups, but millilitres are better when a recipe crosses the Atlantic or when you are scaling it.
The cup is not 250 millilitres everywhere
The metric cup used in Australia and in most metric recipes is exactly 250 millilitres, but the American customary cup is about 237 millilitres, and the Japanese cup is 200 millilitres. That means a recipe that says one cup can mean three different amounts depending on where it was written, and the difference between 237 and 250 millilitres is about 5 percent — enough to matter in baking. Most modern recipes that give millilitres alongside cups use the American cup, so 1 cup means 237 millilitres unless the recipe says metric. If you cook from Australian or New Zealand sources, assume the 250-millilitre cup instead, and adjust the liquid by a tablespoon per cup when converting.