mL to Cups: US, Metric, and UK Cups Explained

Three different cups

The word "cup" hides three sizes. The US customary cup is 236.588 mL, usually rounded to 237 mL or even 240 mL on nutrition labels. The metric cup — standard in Australia, New Zealand, and common in modern European recipes — is a clean 250 mL. The historic UK imperial cup is 284.131 mL, though British cooks today more often weigh in grams or use metric cups.

The difference matters. A recipe calling for 4 US cups needs about 946 mL, but 4 metric cups is 1,000 mL — a 5.7% gap that can throw off a cake. When a recipe's origin is unclear, the metric cup (250 mL) is the safest default for most of the world outside the United States.

A cooking conversion table

Using the US cup at 237 mL: 1/4 cup = 59 mL, 1/3 cup = 79 mL, 1/2 cup = 118 mL, 2/3 cup = 158 mL, 3/4 cup = 178 mL, and 1 cup = 237 mL. Going up: 2 cups = 473 mL and 4 cups = 946 mL (just under a liter). These are the fractions you meet most in baking.

If your recipe is metric (250 mL cup), scale up slightly: 1/2 cup = 125 mL and 1 cup = 250 mL. The neat round numbers are exactly why the metric cup was designed that way — 250 mL is a quarter of a liter, so four cups make a tidy liter.

Dry vs. liquid, and why weighing wins

A cup is a unit of volume, so 1 cup of water is 237 mL whether you call it dry or liquid. But a cup of flour and a cup of water weigh very differently — about 120 g versus 237 g — because their densities differ. That is why professional bakers weigh ingredients in grams rather than scooping cups, which pack differently depending on how you fill them.

For liquids, milliliters and cups convert cleanly. For dry goods, if a recipe gives both cups and grams, trust the grams. If it gives only cups, level them off with a straight edge and note whether the recipe is American (237 mL) or metric (250 mL).

Frequently asked questions

How many mL is one cup?

A US cup is about 237 mL (exactly 236.588 mL). A metric cup is 250 mL, and an old UK imperial cup is about 284 mL, so check which one the recipe uses.

How many cups is 500 mL?

500 mL is 2.1 US cups (500 ÷ 237) or exactly 2 metric cups (500 ÷ 250). The answer depends on which cup you mean.

Is a metric cup the same as a US cup?

No. A metric cup is 250 mL and a US cup is about 237 mL — a difference of roughly 5%, which matters for baking but rarely for a quick soup.

Can I convert dry cups to mL the same way?

The volume conversion is the same — 1 US cup is 237 mL regardless of contents. But weight differs by ingredient, so for accuracy with flour or sugar, weigh in grams instead.