How Many ml in a Cup? US, Metric and UK Cups Compared

There is no single cup. The answer depends on whose recipe you're reading.

The three cups US customary cup: 236.588 ml — American recipes and most food blogs. Metric cup: 250 ml — Australia, New Zealand and modern European recipes. UK imperial cup: 284.13 ml — older British cookbooks. US legal cup (nutrition labels): 240 ml.

Quick conversions from a US cup 1/4 cup = 59 ml. 1/3 cup = 79 ml. 1/2 cup = 118 ml. 3/4 cup = 177 ml. 1 cup = 237 ml. 2 cups = 473 ml.

When the difference bites The 13 ml gap between a US and metric cup is about 5%. For soup, irrelevant. For bread, cake or anything with yeast or a set flour-to-liquid ratio, a 5% error across four cups compounds into a noticeably wet dough.

The reliable fix Weigh dry ingredients. One US cup of all-purpose flour is 120-125 g scooped lightly, but up to 150 g if packed — a 20% swing that no volume conversion can rescue. Water is easy: 1 ml = 1 g.