What this converter works out
Converts a cup measurement into grams for the ingredients most often needed, and handles the three different cup sizes recipes actually use.
A cup measures volume, so every ingredient converts differently: a cup of flour is about 125 g, a cup of sugar 200 g, a cup of honey 340 g. There is no single conversion.
Flour is the awkward one. Depending on whether it is scooped or spooned, the same cup can hold anywhere from 110 to 150 grams, which is enough to change a cake. This page explains why, and why British recipes have always given weights.
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Before you convert
- A cup is a measure of volume, not weight, so every ingredient converts differently. A cup of flour and a cup of sugar differ by about 75 grams.
- Most recipes using cups are American, where a cup is 240 ml. Australian recipes use 250 ml, and older British books sometimes mean a 284 ml breakfast cup.
- Flour is the least reliable ingredient to measure by volume. Depending on whether it is scooped or spooned, the same cup can hold anywhere from about 110 to 150 grams.
Dip a cup into a bag of flour and you compact it; spoon flour in lightly and level it and you do not. The difference can be 30 per cent, which in a cake is the difference between light and heavy. This is the single strongest argument for kitchen scales, and it is why British recipes have always given weights.
How this converter works
Grams = cups × grams per cup × (cup size ÷ 240)Each ingredient has a typical weight for one 240 ml cup, taken from standard baking references. Choosing a different cup size scales that figure proportionally.
These are typical values for correctly measured, unsifted ingredients. Sifted flour weighs less. Packed brown sugar weighs considerably more than loose. Treat the result as a good working figure rather than an exact one, and use scales where precision matters.
Common conversions
| Ingredient | Per cup | Half cup | Quarter cup |
|---|---|---|---|
| Plain flour | 125 g | 63 g | 31 g |
| Strong bread flour | 130 g | 65 g | 33 g |
| Caster or granulated sugar | 200 g | 100 g | 50 g |
| Icing sugar | 120 g | 60 g | 30 g |
| Soft brown sugar, packed | 220 g | 110 g | 55 g |
| Butter | 227 g | 113 g | 57 g |
| Water or milk | 240 g | 120 g | 60 g |
| Honey or syrup | 340 g | 170 g | 85 g |
| Rolled oats | 90 g | 45 g | 23 g |
| Cocoa powder | 100 g | 50 g | 25 g |
A US stick of butter, which American recipes often use instead of cups, is half a cup: 113 g or 4 oz.
Worked example
An American cookie recipe calls for two and a quarter cups of plain flour:
- 2.25 × 125 g = 281 g
- Measured by scooping instead, the same cups could hold as much as 340 g — enough to make the cookies dry and cakey
This is why a recipe that works for its author can fail for everyone else. Weighing removes the variable entirely.
Common mistakes
- Assuming all cups are the same. US 240 ml, Australian 250 ml, older UK 284 ml.
- Using one conversion for everything. Weight per cup varies from 85 g to 340 g depending on the ingredient.
- Scooping flour from the bag. Spoon it in and level it, or better, weigh it.
- Measuring butter in a cup. Weigh it or use the wrapper markings.
- Forgetting whether the recipe means sifted. "One cup sifted flour" and "one cup flour, sifted" are different quantities.
- Using a mug. Mugs vary from 200 to 400 ml.
Frequently asked questions
How many grams is a cup of flour?
About 125 g for plain or self-raising flour in a standard 240 ml US cup, and around 130 g for strong bread flour. The real figure depends on how the cup was filled: scooping compacts the flour and can push it to 150 g or more, while spooning it in lightly and levelling gives closer to 120 g.
Is a UK cup the same as an American cup?
No. Recipes using cups are usually American, where a cup is 240 ml. Australian recipes use a 250 ml metric cup. Older British books occasionally mean a breakfast cup of about 284 ml, which is half an imperial pint. British recipes have generally used weights rather than cups.
Why do different websites give different gram conversions?
Because they measure differently. There is no single correct weight for a cup of flour, only a typical one, and the range between careful and careless measuring is wide enough to matter. Any conversion table is a reasonable average rather than a fact.
Should I sift before or after measuring?
It changes the answer, so follow the wording. "One cup sifted flour" means sift first and then measure, which gives less flour. "One cup flour, sifted" means measure first and sift afterwards. If the recipe is ambiguous, measure first — it is the more common intention.
How much is a stick of butter?
Half a cup: 113 g, or 4 oz. A full cup of butter is 227 g, which is close enough to a standard 250 g British block that recipes often just say a block.
Is it worth buying scales?
For baking, yes, and they are inexpensive. Volume measurement introduces a variable that weight simply removes, and it is the most common reason a well-written recipe produces inconsistent results.
Is what I enter stored?
No. Figures are processed in your browser and never transmitted or retained.
Related tools
References
These organisations publish the guidance and figures behind this page.
- Food Standards Agency — UK food safety guidance for home cooks and businesses
- NHS — eat well — portion guidance and healthy eating advice
Sources are checked at publication and can change — how I choose and check references.