Cups to Grams: Why the Weight Depends on the Ingredient

A cup is a fixed volume of about 237 milliliters, but grams measure mass. Because ingredients have different densities, one cup of each weighs a different amount. A cup of all-purpose flour is roughly 120 grams, while a cup of granulated sugar is about 200 grams and a cup of water is about 237 grams.

This is why serious baking recipes list grams. Weighing removes the guesswork of how full a cup is, which is the biggest source of inconsistent results between two people following the same recipe.

Useful approximate weights for one US cup: all-purpose flour about 120 grams when spooned and leveled, granulated sugar about 200 grams, packed brown sugar about 220 grams, butter about 227 grams (two standard sticks), and powdered sugar about 120 grams.

These are typical values, not universal constants. Bread flour, cake flour, and whole wheat all differ slightly, and cocoa or nut flours differ more. When a recipe gives its own gram figure for a cup, trust the recipe over a generic table.

Flour is the classic trap. Dipping the cup straight into the bag compresses the flour and can add 20 percent or more weight versus spooning it in and leveling the top. That extra flour makes baked goods dense and dry.

Brown sugar is the opposite convention: it is almost always measured packed, pressed firmly into the cup, so its per-cup weight runs higher than granulated sugar. Because packing varies so much, any cup-to-gram figure is an estimate, and a kitchen scale is the reliable fix.

The converter applies the right density for each ingredient so you are not stuck with a single generic ratio.

For soups, stews, and most stovetop cooking, small measuring differences rarely matter. Baking is where precision counts, because the ratio of flour to liquid to fat controls how a recipe rises and sets, and being off by a quarter cup can change the outcome.

If you bake often, weighing in grams is worth the habit. It is faster with fewer dishes, it scales cleanly when you double a recipe, and it makes results repeatable regardless of whose cup you use.