To make cake flour substitute at home, measure 1 cup of all-purpose flour, take 2 tablespoons of that flour out, and stir 2 tablespoons of cornstarch in its place. Do that for every cup of cake flour your recipe calls for, sift the blend twice, and use it exactly like the cake flour the recipe asked for.
It takes about two minutes per cup and costs almost nothing beyond what’s already in your pantry. I keep cornstarch on hand permanently for this reason, and the swap has saved more abandoned bakes than any other baking trick I know. This guide covers the exact ratio, the metric equivalents, how to sift it properly, and what to do when the cake still comes out denser than you wanted.
Table of Contents
What You Need
Everything you need is probably already in the cupboard. The ingredients are two, and the only tool that genuinely matters is something that measures well.
- All-purpose flour. Plain AP flour with nothing added. Don’t use bread flour here; it’s higher in protein and pushes the opposite direction.
- Cornstarch. Plain cornstarch, not cornstarch sugar or a seasoned blend. The same cornstarch you dredge fruit in.
- A dry measuring cup and measuring spoons. Spoon and level the flour, and use a proper 1/4-cup measure for the cornstarch rather than eyeballing it.
- A small bowl and a whisk, fork, or fine mesh sieve. Any one of these will blend the two powders evenly.
- A kitchen scale (optional). Useful if you bake by weight or want to skip volume measuring entirely.
Here’s why the swap works. Cake flour is a wheat flour milled from the soft endosperm, which gives it a protein content of roughly 6 to 8 percent. All-purpose flour sits around 10 to 12 percent, and bread flour runs higher still at 13 to 14 percent. More protein means more gluten, and gluten is the stretchy network that traps gas and gives bread and rustic cakes their chew.
Cornstarch is a pure starch with no wheat protein at all. Swapping two tablespoons of it in for two tablespoons of flour dilutes the protein in that cup by roughly a third, which slows gluten development during mixing. The result bakes into a finer, more tender crumb that behaves a lot like commercial cake flour.
That’s the whole science behind it. No milling, no blending, no special equipment, and about the same result you’d get from a store-bought box in most layer cakes, cupcakes, and sponge-style bakes.
Step-by-Step: How to Make Cake Flour Substitute at Home
Measure the Flour and Cornstarch
Measure 1 cup of all-purpose flour and spoon it into your bowl. Scoop 2 tablespoons of that flour back out and return it to the flour bag, since you’ll want the full cup where you need it later. Now measure 2 tablespoons of cornstarch and add it to what’s left in the bowl.
The most common mistake here is adding cornstarch on top without removing flour first. That leaves you with more than a cup of dry mix and a starch ratio well above the one you want, which is the fast route to a gummy crumb. Removing the flour keeps the total dry volume in the bowl at exactly one cup, which is what the rest of your recipe is calibrated for.
| Cake flour called for | All-purpose flour | Cornstarch | By weight |
|---|---|---|---|
| 1 cup | 7/8 cup (14 Tbsp) | 2 Tbsp (1/8 cup) | 105 g AP flour + 16 g cornstarch |
| 2 cups | 1 3/4 cups | 4 Tbsp (1/4 cup) | 210 g AP flour + 32 g cornstarch |
| 3 cups | 2 5/8 cups | 6 Tbsp (3/8 cup) | 315 g AP flour + 48 g cornstarch |
| 4 cups | 3 1/2 cups | 1/2 cup | 420 g AP flour + 64 g cornstarch |
| 5 cups | 4 3/8 cups | 5/8 cup | 525 g AP flour + 80 g cornstarch |
| 6 cups | 5 1/4 cups | 3/4 cup | 630 g AP flour + 96 g cornstarch |
Those gram figures are the practical route if you own a scale: a level cup of all-purpose flour weighs roughly 120 g, so each cup of homemade cake flour blend lands near 120 g overall, with about 105 g of it flour and 16 g of it cornstarch. Baking communities often state the same ratio differently, as 7/8 cup flour plus 1/8 cup cornstarch, or as one and three-quarter cups of flour plus a quarter cup of cornstarch for every three cups. They’re describing the identical swap.
Scale the ratio for large bakes rather than guessing. A six-cup batch is the biggest I’d mix in advance, since a full cake usually never calls for more than three cups of cake flour at once.
Sift or Whisk Until Uniform
Put the two powders in a bowl and blend them until no white streaks of cornstarch remain. Sifting twice through a fine mesh sieve works well, and it also aerates the blend, which is a bonus for sponge cakes. If you don’t own a sieve, a whisk or a fork in a wide bowl gets the same result in about thirty seconds.
How do you know it’s done? Rub a pinch between your fingers. Properly blended cake flour feels soft and uniform with no gritty, slightly lumpy patches. Gritty pockets of cornstarch mean you still have lumps that will show up as pale, dense spots in the finished crumb.
A food processor works too, and many bakers run the blend through theirs for a few seconds for the finest texture. The honest truth, though, is that sifting matters far less than measuring accurately. Get the ratio right and a quick whisk is genuinely fine. Get the ratio wrong and sifting twice won’t save it.
Use the Substitute in Your Recipe
Treat the blend exactly like the cake flour it replaces. In most recipes that means adding it to the dry ingredients, sifting it in with the baking powder if the recipe sifts its dry ingredients, and then mixing until just combined.
Do not add extra liquid by reflex. A well-made blend usually behaves identically to store-bought cake flour, and thinning the batter is a good way to end up with a dense middle. The one exception: if your recipe specifically calls for a thick, stiff batter, such as some doughnut and biscuit-style formulas, a tablespoon of milk per cup of substitute blend is a reasonable adjustment.
One more thing worth knowing: cake flour usually still contains baking powder or baking soda unless the recipe says otherwise. Substitute the flour one-for-one and leave the leavening exactly as written, or your cake will either sink in the middle or taste soapy.
Common Mistakes
Adding cornstarch without removing flour
Stirring two tablespoons of cornstarch into a full cup of AP flour gives you roughly 14 percent starch, which skews the crumb gummy and dense. Pull the flour out first, then add the cornstarch. The bowl should end up with exactly one cup of dry mix, no more.
Packing the measuring cup
Packed flour is the quiet reason some bakes turn out heavy even when the ratio was right. Scoop, then level the top with the back of a spoon or a straight edge, then use that. Never press or shake the cup to make more flour fit, and never scoop straight from the bag.
Skipping the blend
Dumping both powders into the dry ingredients and starting to mix leaves pockets of concentrated cornstarch that show up as pale specks and uneven texture. Blend the substitute in its own bowl first, every time.
Using the wrong base flour
Bread flour has too much protein for this swap, and whole wheat flour will make any cake taste like a loaf no matter how much cornstarch you add. If bread flour is all you have, use it plain and adjust the recipe, or use pastry flour instead, which already sits close to cake flour at 8 to 9 percent protein.
Overmixing the batter
Once the flour goes in, mix only until the dry streaks disappear. Beyond that point you are developing gluten by hand, which partly undoes the work your cornstarch just did, and that is the most common reason a homemade cake flour cake still feels chewy.
Fixing a dense or gummy cake
If a cake comes out heavy, run through these in order before you blame the flour: did you remove the flour before adding cornstarch, did you level the measuring cup, did you blend the powders evenly, and did you stop mixing the batter early. After the cake is baked the damage is done, but next time those four checks usually explain it.
Storing a pre-mixed batch
A blended batch keeps just as well as the flours it came from, so store it like flour in an airtight container at room temperature, out of sunlight. Expect roughly six months of freshness for the flavor, and use it up sooner if the recipe depends on a very fine, squeaky-clean crumb, since cornstarch can clump slightly over time. Give the container a good shake or whisk before each use. Making it per cup as you bake takes almost no extra effort and avoids the question entirely.
Other pantry substitutes
Cornstarch isn’t the only swap. Arrowroot powder works in the same 2-tablespoon slot and produces an even lighter crumb, though it’s slightly more expensive and less common. Pastry flour is the closest store-bought option since it’s already low-protein, though it’s still a touch heavier than true cake flour. Oat flour blended with cornstarch gives a nuttier, grainier result that suits spice cakes and quick breads rather than a wedding layer. Bread flour is the one to avoid, and plain all-purpose flour on its own will always bake heavier and chewier than the recipe intended.
Making self-rising flour substitute
Self-rising flour is cake flour plus a leavening agent and salt, so build it the same way. For every cup your recipe calls for, mix 1 cup of your homemade cake flour blend with 1 1/2 teaspoons baking powder and a pinch of fine salt, then sift. If your recipe also calls for baking powder, halve the amount you add separately since the blend already contains it. Scones, biscuits, muffins, and quick breads all work this way.
Gluten-free baking
The cornstarch method relies on wheat protein, so it won’t work for celiac or gluten-free baking, and gluten-free bakers should skip it entirely. Look instead for a cup-for-cup gluten-free flour blend that already includes starch, or combine oat flour with cornstarch at a ratio of one cup oat flour to two tablespoons cornstarch for a texture closer to homemade cake flour. Always check that the blend is certified gluten-free, since regular oat flour and cornstarch are frequently cross-contaminated.
Frequently Asked Questions
Can I use cornstarch instead of cake flour?
Not on its own. Cornstarch replaces part of the all-purpose flour rather than standing in for the whole cup, because pure starch gives you a dense, pasty batter with no structure. Use it the swap way: one cup of all-purpose flour with two tablespoons removed and two tablespoons of cornstarch added in their place.
Do I need to sift the cake flour substitute?
Sifting is the tidiest method, not a requirement. A fine mesh sieve sifted twice also aerates the blend, which helps in sponge cakes. In most other bakes a thorough whisk or fork in a wide bowl blends the powders just as well. Measure accurately and blend until no white cornstarch streaks remain, and that is enough.
Can I store homemade cake flour substitute?
Yes. Keep the blended flour in an airtight container at room temperature, away from sunlight and moisture. Expect about six months for the best flavor, though it stays usable longer. Whisk or shake the container before each use, because cornstarch can settle and clump during storage.
Does the substitute work for doughnuts and cupcakes?
It works well for both. Cake-flour doughnut recipes rely on a low-protein flour for a tender crumb, and the cornstarch blend delivers that. Cupcakes, layer cakes, and sponge cakes are all good candidates. Only adjust the liquid if the recipe calls for a deliberately stiff batter, and even then add no more than a tablespoon per cup.
What if my batter looks thinner than the cake flour batter?
Leave it alone first and bake it as written. A thin-looking batter is normal for a proper low-protein blend, and adding liquid to compensate is what produces a dense, gummy center. If the cake still sinks or collapses, the usual causes are overmixing, underbaking, an ungreased pan, or opening the oven door early.
Conclusion
Measure a cup of all-purpose flour, pull out two tablespoons, put two tablespoons of cornstarch in their place, sift or whisk until the white streaks disappear, and use it exactly as you would the cake flour the recipe asked for. Scale that same ratio for every cup, keep the flour level and the batter barely mixed, and the crumb lands tender and light. I refreshed this guide for 2026, and the method has not needed changing since I started using it.
