How Many Grams in a Cup of Flour? 7 Sources Disagree
There is no single correct answer. Trusted sources put a cup of all-purpose flour anywhere from 120g to 142g — an 18% spread. The right number for you depends on how you fill the cup, not which source you believe.
Below: every source, why they disagree, and a tool that gives you your number.
Enough to change a cake from tender to dry.
What each source actually says
| Source | Weight | Stated method |
|---|---|---|
| King Arthur Bakinglowest | 120 g | Spoon into cup, level off |
| Bake From Scratch | 125 g | Spoon and level |
| Washington Post | 126 g | Not specified |
| New York Times | 128 g | Common editorial standard |
| Bon Appétit | 130 g | Not specified |
| AllRecipes | 136 g | Closer to scoop-and-sweep |
| Cook's Illustratedhighest | 142 g | Dip and sweep |
Why they disagree
Every figure above is correct for the method that produced it. Flour is compressible, so the number on the scale is decided almost entirely by how the cup gets filled.
- Dip and sweep — plunge the cup into the bag and level it. The flour compacts. This is the heaviest method and lands near 140g.
- Spoon and level — spoon flour loosely into the cup, then level with a knife. No compaction. Lands near 120–125g.
- Sift first — aerates the flour before measuring. The lightest result, around 115g.
Why King Arthur sits lowest: their flour is milled to a higher protein content and absorbs more liquid, so their recipes call for less flour by weight to reach the same dough consistency. The 120g figure is tuned to their product, not a universal constant.
Find your number
How do you actually fill the cup? Pick the one that matches what you do.
What the AI answers get wrong
We asked three assistants the same question in July 2026. All three returned a single number with no mention that the sources disagree:
“One cup of all-purpose flour weighs approximately 120 grams.”
“A cup of all-purpose flour is about 125 grams.”
Why that matters. Both numbers assume spoon-and-level. If you dip and sweep — which most home bakers do without thinking about it — your cup holds closer to 140g. Follow the AI number while using the scoop method and you are adding roughly 20g of extra flour per cup. Over three cups that is most of an extra half cup, which is the usual reason a cake comes out dry and dense.
The fix that ends the problem
Buy a digital kitchen scale. They cost under $15 and remove the entire question — you weigh 120g or 140g deliberately instead of inheriting whichever method a recipe writer happened to use. Every serious baking source now publishes weights first for exactly this reason.
Frequently asked questions
So how many grams is a cup of flour?
Between 120g and 142g depending on how the cup is filled. Spoon and level gives about 122g, dip and sweep about 140g, sifted about 115g. If a recipe does not state its method, 125–128g is the safest middle assumption.
Which source should I trust?
Whichever matches the recipe you are following. If the recipe is from King Arthur, use 120g. If it is from Cook's Illustrated, use 142g. Mixing a King Arthur weight into a Cook's Illustrated recipe is what actually causes failures.
Does bread flour weigh the same as all-purpose?
Close but not identical. Bread flour is around 120g per cup, whole wheat around 113g, cake flour around 115g. The same filling-method spread applies to each.
Why does the AI give one number if sources disagree?
Language models return the most statistically common answer in their training data, which favours the widely republished 120–125g figure. They are not weighing anything, and they generally do not surface the disagreement unless you specifically ask about measuring methods.
Is a US cup the same as a metric cup?
No. A US cup is 240ml, a metric cup is 250ml, and an imperial cup is 284ml. That is another 4–18% of variation on top of the filling-method spread, which is why weight is the only reliable unit for baking.