Cups to Millilitres: Why Recipes Go Wrong

A recipe that says "one cup of flour" is less precise than it sounds — before you even get to how packed the flour is.

Four cups, four volumes

Cup	Volume	Used in
US customary	236.588 mL	Most American recipes
US legal	240 mL	US nutrition labelling
Metric	250 mL	Australia, NZ, UK modern recipes
Imperial	284.13 mL	Older British recipes
Japanese (gō)	180 mL	Japanese rice cookers

A metric cup is 5.7% larger than a US cup. In a cake, that is the difference between moist and dry.

Spoons differ too

Spoon	US	Metric	Imperial	Australian
Teaspoon	4.93 mL	5 mL	5.92 mL	5 mL
Tablespoon	14.79 mL	15 mL	17.76 mL	20 mL

The Australian tablespoon is four teaspoons, not three. A recipe calling for three tablespoons of baking powder made with Australian spoons delivers 35% more raising agent.

The real problem: volume for solids

Flour is the classic trap. A cup of flour weighs anywhere from 120 g to 150 g depending on whether it was scooped, spooned or sifted — a 25% swing. Professional bakeries work exclusively in grams for this reason.

Approximate weights per US cup:

Ingredient	Grams
Water	237
Plain flour (spooned)	125
Granulated sugar	200
Brown sugar (packed)	220
Butter	227
Honey	340

Note that these are ingredient-specific. There is no universal cups-to-grams conversion, which is why our cooking converter handles volume only.

Sticks of butter

American butter comes in sticks of ½ cup — 113 g or 4 oz. A recipe wanting "1½ sticks" needs 170 g. The wrapper is usually printed with tablespoon markings.

Practical advice

1. Check which country the recipe is from before you start.
2. Buy a digital scale — it removes the entire problem for £10.
3. For liquids, cups are fine; for flour, sugar and butter, weigh.
4. Never mix systems mid-recipe.

Related conversions

• Millilitres to US cups
• Tablespoons to teaspoons
• All cooking units