One US cup of all-purpose flour weighs about 125 g, the figure from USDA FoodData Central used throughout this page. A careful baker who spoons flour into the cup will often get closer to 120 g, and a smaller cup holds less: about 106 g in a Japan cup and about 95 g in a Taiwan rice cup. If you have a scale, the gram figure is always the safer choice.
Why the weight depends on how you measure
Flour is a powder full of air, and it settles in the bag. How you get it into the cup decides how much of that air stays. King Arthur Baking describes a “fluff, sprinkle and scrape” method: loosen the flour in its container, spoon it into the cup until it overflows, then level the top with a straight edge. Measured this way, their test kitchen gets about 120 g per US cup. The USDA lists 125 g without stating its method, which is why the answer box above gives a range of 120 to 125 g rather than a single exact number.
Scooping is the real problem. Pushing the cup into the bag compresses the flour, and a packed cup can reach about 160 g. That extra 35 to 40 g is enough to turn a soft cookie into a dry one. Sifting has the opposite effect: it lightens the flour, so “1 cup sifted flour” (sift, then measure) holds less than “1 cup flour, sifted” (measure, then sift). Humidity and brand also shift the weight slightly, but not as much as technique.
Which cup does your recipe use?
American recipes use the US cup of 236.6 mL, and many US baking books and websites now print grams alongside cups; when they do, the gram figure tells you what the author’s cup actually weighed. Australian recipes use the 250 mL metric cup, which holds about 132 g of flour by the same density. Japanese recipes that mention a cup mean 200 mL, though Japanese baking recipes often list flour in grams anyway.
The Taiwan rice cup is meant for rice, not flour. If a recipe tells you to use the cup from the rice cooker, count about 95 g of flour per cup, but expect some variation because these cups are not made to one standard.
Tips for measuring by volume
- Stir or whisk the flour in its container before you measure, so you start from a loose state.
- Spoon the flour in until it mounds, and do not tap or shake the cup.
- Level with the back of a knife in one sweep, without pressing down.
- For small amounts, a level tablespoon is about 8 g; a heaped one can easily be half as much again.
- When a recipe gives both cups and grams, trust the grams.