Why do recipes give weights instead of cups?

Because a cup of flour can vary by twenty percent depending on how it was filled. Weight removes that variance entirely, which matters most in baking.

Is a US cup the same as a metric cup?

No. A US cup is 236.6 ml and a metric cup is 250, about a six percent difference, which is enough to notice in a small recipe.

ConversionscookingUnited States only

Cooking Measurement Converter

Cooking measures converted by volume, with an approximate weight. A US cup is 236.6 ml and a metric cup is 250, and a cup of flour weighs about half what a cup of water does.

Also called: cups to grams, baking conversion chart.

Millilitres

473.18

2 cup_us is 473.18 ml, 2 US cups, 32 tablespoons or 96 teaspoons. As weight that is about 250.78 g of flour. Flour weight varies by up to twenty percent with how it is packed, which is why baking recipes give grams.

US cups

Metric cups

1.89

Tablespoons

Teaspoons

Grams

250.78

US fluid ounces

On volume against weight

Flour weight varies by up to twenty percent with how it is packed, which is why baking recipes give grams.

How this is calculated

Method and background

How this is calculated

Volume conversions are exact: a US cup is 236.588 ml, a metric cup 250, a tablespoon 14.787 ml. Weight is where it gets unreliable, because it depends on the ingredient and on how it was measured. A cup of flour can vary by twenty percent between scooped and spooned, which is why serious baking recipes give grams. The densities here are typical values, good enough for cooking and not for pastry.

volume converts exactly; weight needs the ingredient density, which is why baking by weight is more reliable

rho: Density

Worked examples

Each of these is asserted on every build. If a change to the engine ever moved one of these answers, the build would fail before the page could print it.

two US cups

Quantity: 2
From: US cup
Ingredient, for weight: Plain flour

Millilitres473.18

2 x 236.588 ml; 473.176 x 0.53

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a metric cup is larger

Quantity: 1
From: Metric cup
Ingredient, for weight: Water or milk

Millilitres250

boundary: the six percent difference

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Method and limits

What it assumes

US customary spoons. Australian tablespoons are 20 ml rather than 15.

What it deliberately does not model

Flour weight varies substantially with how it is packed into the cup.
Density figures are typical, not measured for your ingredient.

Formula version 1.0.0 · definition 1.0.0 · United States · Report a problem with this calculator

Frequently asked questions

Why do recipes give weights instead of cups?: Because a cup of flour can vary by twenty percent depending on how it was filled. Weight removes that variance entirely, which matters most in baking.
Is a US cup the same as a metric cup?: No. A US cup is 236.6 ml and a metric cup is 250, about a six percent difference, which is enough to notice in a small recipe.