US cup vs metric cup

A US cup holds 236.6 ml. A metric cup, used in Australia, New Zealand and much of the rest of the world, holds 250 ml. The metric cup is about 6 percent bigger, so the same recipe measured with the wrong cup drifts by 6 percent on every volume ingredient. This site uses US cups throughout.

Which cup does my recipe mean?

Go by where the recipe was written. American sites, American cookbooks and anything giving temperatures in Fahrenheit mean the 236.6 ml US cup. Australian and New Zealand recipes mean the 250 ml metric cup. British recipes rarely use cups at all; when an older one does, it may even mean the imperial cup of 284 ml, which is best converted to weight before you start.

The legal US cup has one more wrinkle: American nutrition labelling rounds it to exactly 240 ml. That is why measuring jugs sold in the US sometimes mark 240 ml as one cup. For cooking, the 3 ml gap between 236.6 and 240 is noise.

When the 6 percent matters

For a pot of soup or a tray of roast vegetables, never. For baking, it accumulates. A cake with three metric cups of flour measured against a US recipe carries roughly 22 g of extra flour, about two heaped tablespoons, and that shows up as a drier crumb. Yeast bread is more forgiving because you adjust hydration by feel; delicate sponges and macarons are the least forgiving.

The clean fix is the one this whole site is built around: convert the recipe to grams once, using the density of each ingredient, and the cup question disappears. Our converter assumes US cups, so if your measuring set is metric, multiply the cup result by 0.95 or simply weigh instead.

Quick reference

• US customary cup: 236.6 ml, the standard on this site
• US legal cup (nutrition labels): 240 ml
• Metric cup (AU, NZ): 250 ml, about 6 percent more than US
• Old imperial cup (UK): 284 ml, treat with caution
• Japanese cup: 200 ml, used in rice cookers

Related reading: why conversion charts disagree and the density data behind this site.