Cups, Tablespoons and Millilitres: A Recipe Conversion Guide
Recipe conversion looks like simple volume arithmetic and is the most error-prone measurement in ordinary life, because the units are not standard and the ingredients do not cooperate. The Cooking Measurement Converter handles cups, spoons and millilitres.
A cup is not one size
A US cup is 240 ml. A US *legal* cup, used on nutrition labels, is 240 exactly while the customary one is 236.6. A metric cup, used in Australia and New Zealand, is 250 ml. A Japanese cup is 200.
The UK, confusingly, has largely abandoned cups in favour of weighing, which is why British recipes give flour in grams and American ones in cups.
Tablespoons vary too: 15 ml in the US, UK and most of Europe, but 20 ml in Australia. That is a third more, and in something like a raising agent or a spice it is the difference between right and wrong. Teaspoons are 5 ml almost everywhere, which is the one piece of good news.
The real problem is not the units
A cup of flour can weigh anywhere from 120 to 150 grams depending on how it got into the cup. Scoop it straight from the bag and you compact it; spoon it in and level it off and you do not. That is a twenty per cent swing in the main structural ingredient of a cake, from the same measuring cup.
Brown sugar is worse, because the recipe usually means it packed. Chopped vegetables are worse again, because the size of the chop changes how much fits.
So volume is fine for liquids, where a millilitre is a millilitre, and unreliable for anything granular or compressible. Weighing solves it completely, which is why professional and European baking is done by weight and why a cheap kitchen scale improves baking more than any technique.
Useful weights: a cup of flour is about 125 g, caster sugar about 200 g, butter about 227 g, water 240 g. Those let you convert a volume recipe into a weight one once, and then it is repeatable.
Where precision actually matters
Baking is chemistry and tolerates little. Cooking is not: a bit more onion has never ruined anything. So weigh for bread, cakes and pastry; estimate for a stew without guilt.
The exception in savoury cooking is salt, where the volume of a teaspoon depends enormously on the crystal size - table salt is about twice as dense as flaky sea salt for the same spoon.
Common questions
How many ml in a cup?
240 for US, 250 for metric. For most recipes the difference is tolerable; for baking it is not.
How many tablespoons in a cup?
Sixteen US tablespoons. Twelve and a half Australian ones, which is why mixing conventions goes badly.
Should I weigh or measure?
Weigh anything dry, measure anything liquid. For the weights themselves the Weight Converter covers ounces and grams.
What if a recipe says a stick of butter?
A US stick is 113 grams, half a cup.
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