How Many Grams in a Cup of Flour (and Why It Varies)

Ask five different baking sites how many grams are in a cup of flour and you'll probably get five slightly different answers. I used to think this meant one of them was wrong. Turns out they're all sort of right — it really does depend on how you get the flour into the cup in the first place.

Short answer, if you just want a number: 120 grams for a cup of all-purpose flour, spooned into the cup and leveled with a knife. That's the figure most serious baking cookbooks use, and it's the one I use here on this site too. But the "why it varies" part is honestly more useful than the number itself, so bear with me.

The Scoop-vs-Spoon Problem

If you take your measuring cup and just plunge it straight into the flour bag, scoop, and level off the top — you've compacted the flour. It's denser than it should be. That same cup, filled that way, can easily weigh 140-150 grams. That's a 20-25% difference from the spooned version, which in a cake recipe is genuinely enough to make it come out dry or dense.

Spooning the flour into the cup (using a spoon to lightly transfer it, without shaking or tapping the cup) and then leveling with the flat edge of a knife keeps the air pockets in and gets you closer to that 120g figure. It's a small habit change but it matters more than most people realize.

Sifted Flour Weighs Even Less

If a recipe specifically says "1 cup sifted flour," that's lighter still — usually closer to 100-110 grams, because sifting adds even more air into the flour before it goes in the cup. This is why old recipes that call for sifted flour can go wrong if you skip the sifting step and just spoon it in — you'll end up with more flour by weight than the recipe intended.

Why Not Just Always Weigh It?

Honestly? You should, if you have a scale. It's the only method that removes the ambiguity entirely. Every serious home baker I know eventually converts to weighing flour, not because cups are "wrong" exactly, but because grams don't care how you scooped anything. 120g of flour is 120g of flour, full stop.

Different Flours, Different Weights

Bread flour is denser and slightly heavier per cup than all-purpose, mostly because of the protein content. Cake flour is lighter and finer, so it packs less. If a recipe just says "flour" with no other context, all-purpose is a safe assumption.

A Worked Example

A recipe wants 3½ cups of all-purpose flour. At 120g per cup: 3 cups = 360g, plus a half cup at 60g, so 420g total. If you scooped straight from the bag instead of spooning, that same 3½ "cups" could actually be closer to 490-500g of flour — nearly 20% more than intended. That's the kind of gap that turns a soft cookie into a hockey puck.

FAQ

Does it matter if my flour is old or been sitting a while?
A little — flour that's settled in the bag for a long time compacts naturally, which can make scooped measurements even heavier than usual. Fluffing the flour with a spoon before measuring helps.

What about self-rising flour — same weight as all-purpose?
Close enough for most recipes, yes, since it's really just all-purpose with baking powder and salt mixed in.

Is there a "correct" method restaurants use?
Professional kitchens weigh almost everything, flour included — it's faster and more consistent at scale, and it's part of why restaurant recipes rarely translate cleanly to cup measurements at home.

If you're converting other ingredients too, the full breakdown is in our cups-to-grams guide, or just run the numbers directly in the tool.