Cups to grams

There is no such thing as “the” cup-to-gram conversion, for two separate reasons: a cup isn't one volume, and a cup of one thing doesn't weigh the same as a cup of another. Both trip people up, and the second one is what ruins the cake.

The word means at least four different volumes depending on who wrote the recipe:

• US customary — 237 ml. The one in American cookbooks and on American measuring cups.
• US legal — 240 ml. Used on nutrition labels. Close enough to the above that nobody notices, and for once that's fine.
• Metric — 250 ml. Australia, New Zealand and Canada. About 5% bigger than the American one.
• Imperial — 284 ml. Old British recipes, being half an imperial pint. 20% bigger than the US cup, which is enough to notice in anything baked.

If the recipe doesn't say, guess from where it was written. An American blog means 237 ml; an Australian one means 250; a British recipe from before roughly 1980 might mean 284, though modern UK recipes mostly use grams and sidestep the whole thing.

This is also why this site shows grams by default outside the United States, including in countries that say “cup” perfectly happily — an Australian cup measure and an American recipe are a 5% error on every line, silently.

A tablespoon is 15 ml, three teaspoons, almost everywhere — except Australia, where it is 20 ml and four teaspoons. It is the only unit that changes size without changing name in common use, and it is genuinely dangerous: a third extra of anything measured in spoons is usually salt, baking soda, or yeast.

Teaspoons are 5 ml everywhere and can be trusted. Japanese recipes use a 200 ml cup and a 15 ml tablespoon.

A cup of honey weighs nearly three times what a cup of cocoa powder does. Any single “1 cup = N grams” rule is wrong for most of the shelf. The numbers worth knowing:

Based on a 237 ml US cup. Published values vary by a few grams between sources; for anything but bread, a few grams is noise.

This is the big one, and it's the reason serious baking recipes have moved to weight. Dip a cup straight into the flour bag and you compress it: that cup can hold 150 g. Spoon flour in loosely and level it off and you get about 120 g. Same cup, same flour, 25% apart.

Twenty-five percent extra flour is the difference between a tender cake and a dry one, and it is invisible — you followed the recipe exactly. Nothing about grams is more accurate in principle; a kitchen scale is just immune to how you scooped.

Anything fine and compressible has this problem: flour, cocoa, icing sugar, ground almonds. Granulated sugar and liquids don't, which is why sugar is the one cup measurement you can more or less trust.

• 325°F = 160°C · 350°F = 175°C · 375°F = 190°C · 400°F = 200°C · 425°F = 220°C
• Fan or convection: drop 20°C (about 35°F) from the stated temperature, or expect it done sooner. Most recipes quote conventional.
• British gas marks: 3 = 160°C, 4 = 180°C, 6 = 200°C, 7 = 220°C.

Round to the nearest 5°C. 350°F is 176.7°C exactly, and no domestic oven holds a temperature that precisely — most drift by 15°C or more through a cycle.

• Check which cup: 237 ml US, 250 ml metric, 284 ml old imperial.
• Australian tablespoon is 20 ml. Teaspoons are 5 ml everywhere.
• Flour 120 g, sugar 200 g, butter 227 g, water 240 g per US cup.
• Spoon flour into the cup and level it — never scoop.
• For bread and pastry, use a scale. For soup, use whatever.

Every table on this site has a Cups / Grams switch that converts the whole recipe at once and remembers the choice, so you set it once rather than per recipe. It defaults to whichever your country uses.

It converts what the author wrote — it doesn't invent a weight the recipe never gave. If you're also doubling the batch, the scaling guide covers what doesn't multiply. Paste a recipe and try the switch on it.