Baking
All-Purpose Flour Conversion
All-Purpose Flour weighs 120g per US cup.
| Amount | Grams | Ounces |
|---|---|---|
| 1 cup | 120.0 g | 4.23 oz |
| 1/2 cup | 60.0 g | 2.12 oz |
| 1/4 cup | 30.0 g | 1.06 oz |
| 1 tbsp | 7.5 g | 0.26 oz |
| 1 tsp | 2.5 g | 0.09 oz |
| 100 g | 100.0 g | 3.53 oz |
Need a different amount? Use the full Ingredient Converter tool.
All-purpose flour's 120 grams per cup is the single most consequential density figure on this site, simply because more recipes call for it than almost anything else. It's also the ingredient where the spoon-and-level convention matters most: press a measuring cup straight down into an open bag and you compact and over-fill it, commonly landing closer to 140-150g of flour rather than 120g — a fifteen-to-twenty-five-percent overage baked into the recipe before you've even reached for a bowl.
The 120g figure reflects flour that's been fluffed or stirred in its container, spooned lightly into the measuring cup, and leveled off with a straight edge (a knife or the flat back of a spatula) — never packed, tapped, or shaken to settle. This is King Arthur Baking's standard published convention and the one most US recipe developers assume by default even when they don't spell it out.
If you own a kitchen scale, converting a recipe's cup measurements to grams using this figure and weighing your flour directly removes the technique variable entirely — it's the single highest-leverage accuracy improvement available to a home baker, more impactful than almost any other measurement habit.
Because all-purpose flour appears in more recipes than any other single ingredient on this site, it's worth restating the practical habit that follows from its density figure: weighing flour directly on a scale using the 120g-per-cup conversion, rather than trusting a scooped or even a carefully spooned cup, removes essentially all of the technique-driven variability this page's earlier paragraphs describe.
"All-purpose" is itself a somewhat US-specific category — UK "plain flour" is a close but not perfectly identical equivalent, generally sitting at a slightly lower protein content, which is a genuine consideration when converting a British recipe rather than assuming the two flours are chemically identical.
Out of All-Purpose Flour?
See real substitutes with ratios →
How long does it last?
Storage & shelf life →
Frequently asked questions
Why does scooping flour from the bag give a different result than spooning it?
Scooping presses the measuring cup down into the flour, compacting it and pulling in more than a loosely spooned cup would — it can add 15-25% more flour than the recipe's author intended, which is enough to noticeably toughen a cake or cookie.
Is 120g per cup the same for bread flour or cake flour?
No — bread flour is denser (127g/cup) and cake flour lighter (114g/cup), because they're milled differently and have different protein content. Each has its own conversion page with its own accurate figure.
Does sifting flour before measuring change the weight?
Sifting aerates flour and can reduce how much fits in a cup by volume, but this site's figure assumes flour that's been stirred/fluffed, not sifted — if a recipe specifically says "1 cup sifted flour," it may be expecting a slightly different weight than "1 cup flour, sifted afterward," a genuinely confusing but real distinction in older recipes.
Does altitude change how much a cup of flour weighs?
No — altitude affects how flour and leaveners behave once baked (drier air, faster evaporation, lower boiling point), not the physical weight of a cup of flour itself; 120g per cup holds regardless of elevation.
Does this site's flour figure match what a US nutrition label assumes?
Nutrition labels typically use a slightly different reference serving convention than baking's spoon-and-level cup, so small discrepancies between a label's stated serving weight and this site's 120g figure are normal and not a sign either number is wrong.