How Many Grams in a Cup of Sugar? White, Brown, and Powdered
The question how many grams in a cup of sugar has a different answer depending on which sugar is in your pantry, and the difference is bigger than most bakers expect. A cup of powdered sugar weighs almost half of a cup of brown sugar. Swap them cup for cup in a recipe and the result is not a little off, it is a different recipe. Here are the weights, why they differ, and the substitution math that keeps frosting from turning into soup.
How many grams in a cup of sugar, by type
Values use the standard US cup (240 ml). Granulated is spooned and leveled; brown is packed; powdered is sifted.
| Sugar type (1 cup) | Grams | Notes |
|---|---|---|
| Granulated white | 200 g | Spooned and leveled |
| Brown, packed | 220 g | Light or dark; packed firmly |
| Powdered (confectioners') | 120 g | Sifted; unsifted can be heavier |
| Caster (superfine) | 225 g | Finer crystals settle denser |
| Raw / turbinado | 190 g | Coarse crystals, less dense |
The spread is the whole story: 120 grams at the bottom, 225 at the top. Nearly a 2-to-1 range from the same volume measure. That is why I always say sugar is the ingredient where cups are the least honest.
Why sugar types weigh so differently
Three things change the weight of a cup of sugar: crystal size, moisture, and how you pack it.
Crystal size sets the baseline. Powdered sugar is milled to dust, and fine particles trap air, which is why a cup of it weighs only 120 grams despite containing the most actual sugar per spoonful of air. Caster sugar's smaller crystals pack tighter than granulated's, nudging it from 200 to 225 grams.
Moisture is what makes brown sugar heavy. The molasses coating makes the crystals sticky, so they nestle together instead of sliding apart. But moisture only matters if you pack it. A loosely scooped cup of brown sugar can weigh 180 grams; firmly packed, 220. That 40-gram swing is the difference between chewy and greasy in a batch of cookies, and packing is the single most consequential measuring habit in baking.
The substitution math
The rule is simple: substitute sugar by weight, never by volume. If a recipe calls for 200 grams of granulated sugar and you only have powdered, you need 200 grams of powdered, which is about 1 and 2/3 cups, not one cup. If it calls for 1 cup of brown sugar (220 g packed) and you want to use granulated, you need about 1 cup plus 1 tablespoon and a half.
My honest opinion: for frosting and meringue, where sugar is the structure and not just the sweetness, do not substitute at all without a scale. Powdered sugar contains cornstarch that changes how it dissolves and sets. Brown sugar's molasses adds acidity that reacts with baking soda. Weight gets you the right amount; it does not get you the right chemistry.
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Frequently asked questions
How many grams are in a cup of sugar?
It depends on the type. One US cup of granulated white sugar is about 200 grams, packed brown sugar is about 220 grams, and sifted powdered sugar is about 120 grams.
Is brown sugar heavier than white sugar per cup?
Yes, when measured the way recipes intend. Brown sugar is measured packed, which compresses its moist crystals to about 220 grams per cup, versus 200 grams for loosely measured granulated sugar.
Can I substitute powdered sugar for granulated sugar cup for cup?
No. A cup of powdered sugar weighs about 120 grams versus 200 grams for granulated, so a cup-for-cup swap gives you only 60 percent of the sugar. Substitute by weight instead.
How much does a cup of caster sugar weigh?
About 225 grams per US cup. Caster sugar has finer crystals than granulated sugar, so it settles slightly more densely.
How do I measure brown sugar accurately?
Pack it firmly into the cup, pressing it down until it holds the shape of the cup when turned out. Loosely scooped brown sugar can weigh 180 grams instead of 220, a 20 percent shortfall.