Handy Toolshelf

Cake Flour: Cups to Grams

Cake flour is the drama queen of the flour shelf: the same 120 g per cup as all-purpose on the chart, but it punishes rough measuring more than any other flour.

1 cup cake flour = 120 g (King Arthur Baking — listed as unbleached cake flour, spooned & levelled).
Decimals (2.5), fractions (1/2) and mixed numbers (1 3/4) all work.
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Why cake flour demands a gentle hand

Cake flour is milled finer and from softer wheat than all-purpose, which makes it both lighter in the hand and far more compressible. The King Arthur chart lists it — as "Unbleached Cake Flour" — at 120 g per cup, the same as all-purpose and bread flour. But that equality only holds for a properly filled cup: spooned in loosely and levelled. Drag a cup through the cake flour box and the powder packs down eagerly; of all the flours on this site, cake flour's scooped weight strays furthest from its charted weight, and an over-floured cake batter turns out tough and tunnels — the exact opposite of what cake flour was bought for.

Sifting complicates things further, because cake recipes so often ask for it. If the recipe says "1 cup sifted cake flour", the flour is sifted before it meets the cup — sift, then spoon the aerated flour in gently and level, accepting that a sifted cup is mostly air and weighs less than the chart's unsifted 120 g. If it says "1 cup cake flour, sifted", measure the 120 g first and sift it into the bowl afterwards. When a recipe gives a weight, skip the riddle entirely: weigh 120 g per cup and sift (or don't) as the method describes.

Swapping cake flour without wrecking the cake

Because cake flour and all-purpose flour share the 120 g chart weight, running out of one is not a weighing emergency — convert by weight as normal and the recipe's totals survive. What changes is texture: cake flour's softness is what makes a crumb fine and tender, so an all-purpose swap gives a slightly sturdier cake, and a cake flour swap in a bread recipe gives a loaf that can't hold its structure. The scale can't tell you any of that; it can only promise that 120 g is 120 g.

Storage matters for this flour more than most: cake flour clumps readily in a humid kitchen, and clumps break the spoon-and-level fill. Keep it sealed, and if the box feels lumpy, sift the flour into a bowl before measuring from it — then spoon, never scoop, from the sifted pile.

Frequently asked questions

How many grams is 1 cup of cake flour?

120 grams per US cup on the King Arthur Baking chart, where it is listed as unbleached cake flour — spooned and levelled, like every flour on this site.

Does sifted cake flour weigh the same as unsifted?

No. Sifting aerates the flour, so a cup of sifted cake flour weighs less than the chart's 120 g unsifted cup. Follow the recipe's word order: 'sifted cake flour' means sift then measure; 'cake flour, sifted' means measure then sift.

Can I use all-purpose flour instead of cake flour by weight?

The weights match — both are 120 g per cup on this chart — so the conversion is safe. The texture will differ: all-purpose makes a slightly sturdier crumb, because cake flour's softness, not its weight, is what you're buying.

Why is cake flour so easy to over-measure?

It is milled very fine and compresses readily. A scooped or tapped cup packs in well over the charted 120 g, which toughens cakes. Spoon it in loosely and level without pressing.

Data sources: King Arthur Baking Ingredient Weight Chart and USDA FoodData Central. Weights are per US customary cup (236.588 mL); other cup sizes are scaled by volume ratio. See the data sources & method page for how values were chosen.