Cup sizes around the world, and the glasses that count as cups

Recipes say "one cup" and mean 236.6 millilitres in America, 250 in Australia, 200 in Japan and 284 in a British book old enough to use imperial. The spread is wide enough to ruin a cake, and the more interesting half of the problem is the vessels that were never sold as measures at all.

Every cup we hold, largest first

Volumes from our unit registry, each with its own source.

The vessels that are not measuring cups

Half the list above was never manufactured as a measure. A Brazilian copo americano is a drinking glass, the small ribbed tumbler that has been on every bar in Brazil since the 1940s. A Slavic granchak is the faceted glass from a Soviet canteen. A French pot de yaourt is the empty yogurt pot, washed out and used as a scoop, which is why so many French cake recipes are written in pots rather than grams. These are objects a kitchen already owned, promoted to units because everyone owned the same one. That is a different kind of standard from a stamped measuring cup, and it fails differently: the object drifts, the recipe does not.

Two corrections worth making

The copo americano is 190 millilitres, and a good deal of the internet says 200. The manufacturer, Nadir Figueiredo, which has made the glass since 1947, publishes 190 as the standard size, and since that is the brim-full capacity, 200 is not a rival convention: it is more than the glass holds. Some Brazilian baking sites round up to 200 and say that is what they are doing, which is a fair simplification, clearly labelled. A page that prints 200 as the size of the glass is repeating an error.

The granchak is harder, because the sources disagree about what the object is rather than how big it is. UNIAN describes one glass with two fill levels: 200 millilitres to the rim band and 250 to the smooth edge. Gastronom.ru prints two separate glasses, a thin one at 250 and a faceted one at 200. Both framings are in circulation, and a recipe saying "one glass" gives you no way to tell which its author meant. We keep both figures with both readings attached rather than picking one silently, on the principle the methodology page sets out.

Knowing the volume does not give you the weight

The obvious next step is arithmetic: if a Japanese cup is 200 millilitres and an American one is 236.6, scale the grams by the ratio. It does not work. The Japanese standard tables weigh a cup of flour at 110 g. Scaling our 120 g US cup by volume predicts about 101. The cup is 15 percent smaller and the flour comes out only 8 percent lighter, because a smaller cup packs slightly differently and because the Japanese tables measured rather than calculated. Cup volumes tell you which vessel the author held. For grams, our ingredient masters carry the figure each authority weighed.

The pairs that catch people out

The dangerous gaps are the small ones. A metric cup runs 6 percent over a US cup, close enough to look like rounding and large enough to matter across a batch. A Brazilian xicara at 240 millilitres sits between the two. The Spanish taza is published at three sizes depending on the country and the decade: 200 in older Spanish books, 240 in modern Spanish and Mexican ones, and 250 across most of Latin America, which our Spanish and Latin American page takes apart. Meanwhile the large differences are safer, because nobody mistakes an imperial 284 millilitre cup for a Japanese 200 one once they know both exist. The Japanese kitchen has two cups at once, the 200 millilitre cooking cup and the 180 millilitre go that ships with rice cookers, which our rice master takes apart. And a French pot de yaourt at 125 millilitres is barely half a US cup, so a recipe in pots read as cups doubles everything.

Questions about cup sizes

Which cup does an American recipe mean?

The customary cup, 236.6 ml. The 240 ml legal cup exists too, but it is used for nutrition labels rather than recipes, so a US recipe almost always means 236.6.

Is a metric cup close enough to a US cup?

It is 6 percent bigger, which passes unnoticed in a soup and shows up in a cake. Over four cups of flour the gap is most of an extra cup.

Can I work out grams from the cup size?

Not reliably. A Japanese 200 ml cup of flour is 110 g measured, while scaling our 120 g US cup down by volume predicts about 101. The tables weighed it; the arithmetic guesses.

Three more things a foreign recipe assumes you know: the oven scale, on oven temperatures; the yeast packet, on the yeast converter; the number on the flour bag, on flour types; the eggs, which Europe and America grade differently, on egg sizes; and a whole cuisine whose cup is the only hard part, on Japanese recipe measurements, Eastern European measurements, UK imperial measurements, Australian recipe measurements, French recipe measurements, Brazilian recipe measurements, Italian recipe measurements, Spanish and Latin American measurements and Polish recipe measurements, all indexed on the world measures hub.

Sources

Volumes from our unit registry, each entry sourced individually: NIST for the US cups, Standards Australia and New Zealand publishers for the metric cup, the Kagawa Nutrition University tables for the Japanese cup and go, Nadir Figueiredo for the copo americano, UNIAN and gastronom.ru for the two readings of the granchak, and French, Polish, Italian and Spanish sources for the rest. Full citations on the sources page.