Best Cake Flour Substitutes (With Ratios)
The best cake flour substitute is homemade: measure 1 cup (125 g) all-purpose flour, remove 2 Tbsp, add back 2 Tbsp cornstarch, and sift together twice. By weight, that's about 105 g flour plus 15 g cornstarch for each 120 g of cake flour.
Cake flour substitutes and ratios
| Substitute | Amount per 1 cup cake flour | Best for | Why it works |
|---|---|---|---|
| All-purpose flour + cornstarch | 1 cup AP minus 2 Tbsp, plus 2 Tbsp cornstarch | Layer cakes, cupcakes, sponge | Starch dilutes protein from about 11% to near 9% |
| Cake and pastry flour | 1 cup | Any cake, biscuits, pie crust | Already low in protein (about 7–9%) |
| Pastry flour | 1 cup | Cakes, muffins, scones | Soft wheat, about 8–9% protein |
| All-purpose flour + arrowroot or potato starch | Same as cornstarch version | Corn-free baking | Any fine starch dilutes the protein |
| All-purpose flour alone | 1 cup minus 2 Tbsp | Quick fix, sturdy cakes | Less flour means less gluten; crumb is a little firmer |
| Gluten-free 1:1 flour blend | 1 cup by weight | Gluten-free cakes | Mostly starches, so naturally tender |
Why cake flour makes softer cakes
The difference between flours is mainly protein. Cake flour comes from soft wheat with roughly 7–9% protein, compared with about 10–12% for all-purpose and 12–14% for bread flour. When flour meets water and is mixed, two proteins, glutenin and gliadin, link into gluten, an elastic network. A little gluten holds a cake up. Too much makes it chewy and bready.
Cornstarch is pure starch with no gluten-forming protein. Swapping some flour for it lowers the overall protein, so the network is weaker and the crumb finer and softer. Starch also gelatinizes as the cake bakes, from about 60 °C / 140 °F (higher in sugary batters), absorbing water and helping set a tender structure.
Many US cake flours are also bleached with chlorine, which slightly acidifies the flour and helps its starch absorb more liquid and fat. That's why they can carry very high sugar ratios without collapsing. A homemade swap can't copy that part.
Chef Fizz says: Weigh your flour. One "cup" can range from 120 to 150 g depending on how you scoop, and that's a bigger difference than switching flours.
When not to swap
- Angel food and chiffon cakes, where the recipe relies on bleached cake flour's ability to hold lots of sugar. Homemade swaps can sink slightly; use real cake flour if you can.
- High-ratio cakes with more sugar than flour by weight. Same issue.
- Bread flour as a cake flour swap. Too much protein gives a tough, rubbery cake.
- Cakes you mix for a long time. Even with a swap, overmixing builds gluten; mix just until combined.
Questions
Can I use all-purpose flour instead of cake flour?
Yes. For the closest result, remove 2 Tbsp flour from each cup and replace it with 2 Tbsp cornstarch. Plain all-purpose works too, but the cake will be slightly denser and chewier.
Why do you sift homemade cake flour?
Sifting evenly blends the cornstarch through the flour and aerates it. Unmixed pockets of starch can leave the crumb uneven.
Is cake and pastry flour the same as cake flour?
Close enough for most recipes. Canadian cake and pastry flour has about 7–9% protein, similar to US cake flour, and swaps 1:1.
Can I use self-raising flour instead of cake flour?
Only if you remove the recipe's baking powder and salt. Self-raising flour is usually higher in protein than cake flour, so the crumb will still be a little firmer.