How Many ml in a Cup? US 237, Metric 250, UK 284

The answer depends on which cup your recipe means. A US cup is 236.59 ml, a metric cup is 250 ml, and an imperial cup is 284.13 ml — a 20% spread that changes a bake.

The direct answer

1 US customary cup = 236.588 ml, normally rounded to 237 ml or 240 ml in nutrition labelling. Most American recipes and blogs mean this cup.

Metric cup (Australia, NZ, Canada)

1 metric cup = exactly 250 ml. If a recipe is written in Australia or New Zealand, use 250 ml.

Imperial cup (older UK recipes)

1 imperial cup = 284.13 ml, based on 10 imperial fluid ounces. Rare in modern UK cookbooks, which use grams and millilitres instead.

Fast conversions

1/4 cup = 59 ml · 1/3 = 79 ml · 1/2 = 118 ml · 3/4 = 177 ml · 1 cup = 237 ml · 2 cups = 473 ml · 4 cups = 946 ml (US).

Which one should you use?

Match the recipe's origin. If unknown, use 240 ml — it sits between the US and metric cup and errs small enough for most savoury cooking.

When precision matters

For bread, pastry and custards, switch to grams. Flour packed into a cup can vary by 25% in weight, which no volume conversion can fix.

How this guide is researched and fact-checked

This article is produced by the ToolKit Pro Measurement Desk using ai-assisted research with human editorial verification against primary sources, and is checked by a human editor at the ToolKit Pro editorial desk before publication. Every number, formula and threshold quoted here is traced back to a primary standards body or health authority rather than to another blog, and each figure is re-computed with our own calculators so the worked examples and the live tools on this site always agree. When a definition changes — as with the 2019 SI redefinitions — the affected articles are re-checked and the “updated” date above is bumped.

Produced by: ToolKit Pro Measurement Desk — Unit conversion & measurement standards
Method: AI-assisted research, human-verified against primary sources
Reviewed by: ToolKit Pro editorial desk (human review)
Last reviewed: 2026-08-19
Corrections: spotted an error? Tell us and we will fix and re-date the page.

Sources & further reading

BIPM — The International System of Units (SI Brochure)
NIST — Guide for the Use of the International System of Units
WHO — Body weight & health guidance

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