Cups to Grams Converter: US Recipes in UK Weights

American recipes measure by volume, so a cup of flour and a cup of sugar weigh very different amounts. One US cup of plain flour is about 120g, but a cup of caster sugar is about 198g and a cup of butter 227g. Pick the ingredient, type the amount as the recipe gives it (fractions like 1 1/2 or ¾ are fine), and get the weight to put on your scales. It works the other way too, if you want to turn grams back into cups.

Why cups do not convert to one fixed weight

A cup is a measure of space, not weight. Flour is light and full of air, sugar crystals pack tightly, and butter is solid fat, so the same cup holds a different mass of each. That is why a single "1 cup = X grams" rule gives wrong answers, and why British recipes, written by weight, tend to come out more consistently.

The weights above assume the spoon-and-level method used by American recipe writers: spoon the ingredient lightly into the cup and sweep the top flat with a knife. Dipping the cup straight into a bag of flour compresses it, so you get more flour than the recipe intended and a drier, heavier bake. Brown sugar is the exception: American recipes expect it pressed firmly into the cup, and the figure here assumes that.

Which cup is your recipe using?

• US cup, 237ml: anything from an American website or book. If in doubt, it is this one.
• Metric cup, 250ml: Australian and New Zealand recipes, and most Canadian ones. It holds about 6% more than a US cup.
• Old British cup, 284ml: half an imperial pint, found in some older British cookbooks. Modern UK recipes use grams instead.

Liquids are the easy case. Water, milk and cream weigh close to 1g per ml, so a US cup of milk is roughly 240g and you can measure it in a jug at 240ml. Heavy, sticky syrups are the opposite: a cup of honey weighs well over 300g, so weighing it straight into the bowl on the scales is far less messy than filling a cup.