How many mL in a cup? US, metric and UK cups
Three different cups share the name: 236.6 mL in the US, 250 mL in metric recipes and 284 mL Imperial. Here is which one a recipe means.
By Akash Yadav Updated 25 October 2026
Short answer
A US cup is 236.588 mL
One US cup is exactly 236.5882365 mL. That is 8 US fluid ounces, and it is exact because the cup is a fraction of a gallon rather than a measured amount. A metric cup is 250 mL, and an Imperial cup is 284.131 mL.
So the word "cup" alone does not give one answer. The country the recipe came from decides, and the gap is large enough to matter in baking: a metric cup is 5.7% bigger than a US cup, and an Imperial cup is 20.1% bigger. This page gives the millilitres for each one and the chart for the amounts recipes use.
Four cups
One cup, four different sizes
These are the four cups a recipe or a label can mean. The last column is useful when a recipe is American but your measuring cup is metric.
| Cup | Millilitres | US cups |
|---|---|---|
| US customary | 236.5882 mL | 1 |
| Metric | 250 mL | 1.057 |
| Imperial | 284.1306 mL | 1.201 |
| US label | 240 mL | 1.014 |
The US customary cup is the one in American recipes and on US measuring-cup sets: 8 US fluid ounces. The metric cup is used in Australia, New Zealand, Canada and most modern UK recipes. The Imperial cup is the older British measure, 10 Imperial fluid ounces or half an Imperial pint. The US label cup is the serving-size convention on US nutrition labels.
The US label cup is a rounding convention, not a measuring cup: it is 1.4% above the true US cup, which is why a label can say "1 cup (240 mL)" while a US measuring cup holds 236.59 mL.
Chart
Cups to mL chart
Read a row across for the same number of cups in each system. The columns are not equal volumes: 5.7% separates the US and metric cups, and 20.1% separates the US and Imperial ones.
| Cups | US mL | Metric mL | Imperial mL |
|---|---|---|---|
| 1/4 cup | 59.15 | 62.5 | 71.03 |
| 1/3 cup | 78.86 | 83.33 | 94.71 |
| 1/2 cup | 118.29 | 125 | 142.07 |
| 2/3 cup | 157.73 | 166.67 | 189.42 |
| 3/4 cup | 177.44 | 187.5 | 213.1 |
| 1 cup | 236.59 | 250 | 284.13 |
| 1 1/2 cups | 354.88 | 375 | 426.2 |
| 2 cups | 473.18 | 500 | 568.26 |
| 3 cups | 709.76 | 750 | 852.39 |
| 4 cups | 946.35 | 1000 | 1136.52 |
The 1/3 and 2/3 rows are the ones most tables skip, and they are the amounts a recipe is most likely to ask for when it is not a round number. For a value not in the chart, the cups to milliliters converter does the arithmetic.
Which one
Which cup does the recipe mean?
- A US recipe or a US measuring cup: the customary cup, 236.59 mL. This is the default on this site and on the cups to milliliters page.
- An Australian, New Zealand or Canadian recipe: the metric cup, 250 mL. A recipe from those countries already means 250 mL per cup, so there is nothing to convert.
- A British recipe: modern ones use the 250 mL metric cup. Older ones may mean the Imperial cup, 284.131 mL. The UK has no legal cup: the Weights and Measures Act 1985 defines the gallon and the fluid ounce, not a cup.
- A US nutrition label: the 240 mL labelling cup, from 21 CFR 101.9(b)(5)(viii). It exists so serving sizes are comparable, not so you can measure with it.
A mug or a coffee cup is not a measuring cup. Drinking vessels vary too much to convert from, so use the millilitre marking if the cup has one, or a measuring cup if it does not.
Why the number
Why a US cup is 236.588 mL and not 250
The US cup is a fraction of a gallon, and the gallon is defined in cubic inches. A US gallon is 231 cubic inches (NIST Handbook 44, Appendix C), so a cup is 231 ÷ 16 = 14.4375 cubic inches. One inch is exactly 2.54 cm, which makes a cubic inch 16.387064 mL. Multiply the two and you get 236.5882365 mL — the same number as the US cup, with the rounding gone.
The metric cup went the other way: it is a round fraction of a liter, 250 mL, because a liter is the base unit and a quarter of it is a convenient amount. Neither system is more accurate; they are round numbers in different places.
For a quick estimate, treat a US cup as 240 mL. That is 1.4% high, which is fine for soup and not for a cake. The exact figure to remember is 236.59 mL.
Going the other way
Metric millilitres in US cups
If a metric recipe gives millilitres and your cup is American, this is the direction you need. The milliliters to cups converter handles any value; these are the common ones.
- 250 mL is 1.057 US cups — exactly 1 metric cup.
- 500 mL is 2.113 US cups, or exactly 2 metric cups.
- 1 liter is 4.227 US cups, or exactly 4 metric cups.
In practice, do not convert a metric recipe into US cups and back. Measure the millilitres directly if you can, because each conversion adds a rounding step to a measurement that was already approximate.
Common questions
Cup questions people actually ask
How many mL is a UK cup?
An Imperial cup is 284.131 mL, but a modern British recipe almost always means the 250 mL metric cup. If a British recipe is old enough to use Imperial units throughout, assume the Imperial cup; if it also gives grams, it is metric.
How many mL is an Australian cup?
Exactly 250 mL. Australian, New Zealand and Canadian recipes use the metric cup, which is about 1.057 US cups.
Is 250 mL a cup?
Yes: 250 mL is exactly 1 metric cup. In US cups it is about 1.057, so a US recipe asking for 1 cup wants about 237 mL, not 250.
How many cups is 500 mL?
About 2.113 US cups, or exactly 2 metric cups.
Does a cup of flour weigh the same as a cup of water?
No. Both take up the same volume, but flour is much less dense than water, so a cup of flour weighs less. Cups measure space, not weight. For anything where the weight matters, use grams: the cups to ounces page covers the fluid-ounce side, and a kitchen scale is the only reliable way to weigh dry ingredients.
The converters for this page are cups to milliliters, milliliters to cups, ounces to cups and cups to ounces. For the ounce itself, the guide to the fluid ounce covers US, UK and weight ounces; the cups in a quart guide takes the same question one size up. The definitions behind every number here are on the methodology page.
Use it
Converters in this guide
- Cups to Milliliters cup → mL
- Milliliters to Cups mL → cup
- Ounces to Cups fl oz → cup
- Cups to Ounces cup → fl oz
Every figure in this guide is computed at build time from the same conversion engine as the converters it links to, and the factors behind it are the defining standards listed on the methodology page. Nothing here is typed by hand from a template.
Keep reading
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