1 cup of all-purpose flour in grams — 120 g.

Why 120 g per cup

All-purpose flour is the most-asked-about ingredient in baking — and the one where measurement method matters most. The 120 g/cup figure is the King Arthur Baking standard.

Flour is the trickiest ingredient to measure by volume. A cup of all-purpose flour can weigh anywhere from 113 g (gently spooned) to 150 g (scooped and packed) — a 30 % spread that's the difference between a tender cake and a tough one. The canonical 120 g/cup figure used here matches King Arthur Baking's reference, which assumes the spoon-and-level method: fluff the flour in its container, spoon it gently into the measuring cup, and level the top with a straight edge. Any time a recipe matters, weigh.

The most accurate way to measure all-purpose flour

For recipes where the outcome matters — bakes, doughs, anything leavened — measure all-purpose flour on a kitchen scale set to grams. Set the bowl on the scale, press tare to zero, then add until the readout matches the gram value the recipe calls for. This removes the largest source of cup-to-cup variation: how you scoop.

The cup-based numbers on this page assume the “spoon and level” method — fluffing the ingredient in its container, spooning it into the cup, and levelling the top with a straight edge. Scooping directly with the cup packs more in, and can push the gram value up by 20-30 % for fluffy ingredients like flour and cocoa.