All-purpose flour vs Cake flour
Cake flour is milled finer and has less protein, about 7 to 9 percent against all-purpose flour's 10 to 12. Less protein means less gluten, so cakes come out softer and more tender. To stand in for 1 cup of cake flour, measure 1 cup of all-purpose, take out 2 tablespoons, and add 2 tablespoons of cornstarch. Use cake flour for delicate layer cakes; all-purpose is fine for sturdier bakes like muffins and bar cookies.
At a glance
| Ingredient | Grams per cup | Type | Key trait |
|---|---|---|---|
| All-purpose flour | 120 g | Flours & Starches | Spoon the flour into the cup and level it off — scooping straight from the bag packs it down and can add up to 20% more flour than a recipe intends. |
| Cake flour | 120 g | Flours & Starches | Cake flour is very finely milled — sift it before measuring for the lightest possible crumb. |
How to swap all-purpose flour and cake flour
- 1 cup AP = ⅞ cup cake flour + 2 tbsp cornstarch (for cake-flour recipes) (America's Test Kitchen)Use when a recipe calls for cake flour and you only have AP; for the reverse, equal parts bread + cake flour by weight approximates AP.
- 1 cup cake flour = ⅞ cup all-purpose flour (14 tbsp) + 2 tbsp cornstarch, sifted together (King Arthur Baking / America's Test Kitchen)Cornstarch dilutes the AP flour's protein to mimic cake flour's tender crumb. Sift the blend two or three times so the cornstarch distributes evenly.
Full conversions: All-purpose flour converter · Cake flour converter. More swaps: All-purpose flour substitutes · Cake flour substitutes.
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* Conversion figures are typical average weights for one US customary cup (236.6 ml), based on the King Arthur Baking Ingredient Weight Chart and cross-referenced with the U.S. Department of Agriculture FoodData Central database. Actual weight varies with packing, brand and humidity — see our methodology.