How do I make cake flour?
The weights to swap for the amount your recipe actually asks for. Cake flour, self-raising, bread flour, in grams or cups.
Free. No signup needed.The short answer
Cake flour is plain or all-purpose flour with an eighth of its weight swapped for cornflour, which Americans call cornstarch. So 340 g of cake flour is 298 g of plain flour and 43 g of cornflour, and 125 g, one US cup, is 109 g plus 16 g. Sift them together twice. For self-raising flour, add two level teaspoons of baking powder per 150 g of plain flour, and in the US a teaspoon and a half per cup plus a quarter teaspoon of salt.
How do I make cake flour?
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What the recipe wants
To make 300 g of Cake flour
Plain flour
263 g
Cornflour
38 g
Weigh both into a bowl and sift them together twice. The sifting is not optional, it is what makes the result behave like cake flour rather than like flour with cornflour in it.
This is the one-cup rule worked out for your amount: an eighth of the weight is cornflour, the rest is plain flour. It lowers the protein and softens the crumb, which is the whole point.
Why it matters
Cake flour is 7 to 9 percent protein. Soft and low protein, so it makes a fine, tender crumb. What a light sponge wants. Plain flour is 10 to 12 percent, which is the gap this closes.
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Start free trialFlour substitute charts
| Cake flour needed | In cups | Plain flour | Cornflour |
|---|---|---|---|
| 125 g | 1 cup | 109 g | 16 g |
| 200 g | 1 1/2 cups | 175 g | 25 g |
| 250 g | 2 cups | 219 g | 31 g |
| 300 g | 2 1/2 cups | 263 g | 38 g |
| 340 g | 2 3/4 cups | 298 g | 43 g |
| 400 g | 3 1/4 cups | 350 g | 50 g |
| 500 g | 4 cups | 438 g | 63 g |
An eighth of the weight is cornflour, which Americans call cornstarch and which is the same thing. Sift the two together twice. That step is what actually makes it behave like cake flour rather than like flour with cornflour in it.
Self-raising flour from plain
| Plain flour | UK baking powder | US baking powder | US salt |
|---|---|---|---|
| 125 g1 cup | 1 3/4 tsp | 1 1/2 tsp | 1/4 tsp |
| 200 g1 1/2 cups | 2 3/4 tsp | 2 1/2 tsp | 1/2 tsp |
| 250 g2 cups | 3 1/4 tsp | 3 tsp | 1/2 tsp |
| 300 g2 1/2 cups | 4 tsp | 3 1/2 tsp | 1/2 tsp |
| 340 g2 3/4 cups | 4 1/2 tsp | 4 tsp | 3/4 tsp |
| 400 g3 1/4 cups | 5 1/4 tsp | 4 3/4 tsp | 3/4 tsp |
| 500 g4 cups | 6 3/4 tsp | 6 tsp | 1 tsp |
UK self-raising flour contains no salt. US self-rising flour does, about a quarter teaspoon a cup, which is why an American recipe built on it tastes flat when a British baker swaps in self-raising, and salty the other way round.
What each flour is, and what it does
| UK name | US name | Protein | What it does |
|---|---|---|---|
| Cake flour | Cake flour | 7 to 9% | Soft and low protein, so it makes a fine, tender crumb. What a light sponge wants. |
| Plain flour | All-purpose flour | 10 to 12% | The middle of the range, and the one most recipes assume when they just say flour. |
| Self-raising flour | Self-rising flour | 9 to 11% | Plain flour with the raising agent already in it. UK versions have no salt, US ones do. |
| Strong bread flour | Bread flour | 12 to 14% | High protein, so it builds gluten and chew. Too strong for a sponge, right for bread. |
| Wholemeal flour | Whole wheat flour | 13 to 15% | Carries the bran and germ, so it drinks more liquid and bakes denser. |
Protein is the whole story. It is what turns into gluten when flour meets liquid, and gluten is chew. Low protein gives a tender crumb, high protein gives structure and bite.
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How flour swaps work
Flours differ by protein, so making one out of another is arithmetic. The published rules only ever cover a single cup, which is never the amount you need.
Any amount
The one-cup rule, written as a fraction
Every published cake flour rule is the same sentence: take a cup of plain flour, remove two tablespoons, put two tablespoons of cornflour back. It is correct, and it is useless the moment a recipe asks for 340 g. Two tablespoons is an eighth of a cup, so the rule is really an eighth of the weight, whatever the weight is. That makes 340 g of cake flour into 298 g of plain flour and 43 g of cornflour. If the size of the bake is changing too, scale the recipe up or down first, then convert the flour.
Protein
Protein is the only real difference
Flour is sorted by how much protein it carries, because protein becomes gluten and gluten is chew. Cake flour is 7 to 9 percent, plain and all-purpose 10 to 12, self-raising 9 to 11, strong bread flour 12 to 14, wholemeal 13 to 15. Cornflour has no protein at all, so swapping an eighth of the weight for it pulls plain flour down to roughly 9 or 10 percent. That lands at the top of the cake flour band, or a shade over it, and in a sponge you cannot taste the difference.
Self-raising
The salt is where the UK and the US split
UK self-raising flour is plain flour and baking powder. Nothing else. US self-rising flour carries salt as well, about a quarter teaspoon a cup, which is why an American recipe made with British flour tastes flat and a British one made with American flour tastes salty. The UK measure is two level teaspoons of baking powder per 150 g of plain flour. The US measure is a teaspoon and a half plus a quarter teaspoon of salt per cup, and a cup is 125 g. It is the same trap as UK and US egg sizes, where the word matches and the ingredient does not.
The one that cannot be done
Self-raising back to plain is impossible
You cannot take baking powder out of flour, and any page offering a method for it is guessing. What you can do is use the self-raising flour as it is and leave out the raising agent the recipe asks for, because it is already in the bag. Three hundred grams of self-raising carries about four teaspoons of baking powder. For shortcrust pastry, or anything meant to stay flat, that does not work either and you need a different flour.
Two names
Same flour, different word
Cornflour is cornstarch. Plain is all-purpose, wholemeal is whole wheat, and strong flour is bread flour. Nothing changes in the bag, only on the label. One real trap: in the US, corn flour means finely ground maize and it will ruin a sponge, so ask for cornstarch. For the swaps that are not flour, the baking substitution calculator has butter, buttermilk and sugar, and how much batter your tin takes tells you how much flour to convert in the first place.
FAQ
Common questions
How do I make cake flour substitute?
Take an eighth of the weight out as plain or all-purpose flour and put the same weight back in as cornflour, which Americans call cornstarch. For 340 g of cake flour that is 298 g of plain flour and 43 g of cornflour. Sift the two together twice. The sifting is what makes it behave like cake flour rather than like flour with cornflour in it.
How much cornstarch do I add to make cake flour?
Two level tablespoons per cup, about 16 g per 125 g, with the same weight of flour taken out first. By weight it is always an eighth, so 250 g of cake flour is 219 g of plain flour and 31 g of cornstarch. The one-cup rule everyone quotes is that same number written for a single cup.
Is cake flour the same as plain flour?
No. Cake flour is 7 to 9 percent protein and plain or all-purpose flour is 10 to 12. Protein turns into gluten when it meets liquid, and gluten is chew, so cake flour gives a finer and more tender crumb. Adding cornflour is how you bring the protein down.
How do I make self-raising flour from plain flour?
Two level teaspoons of baking powder per 150 g of plain flour in the UK. In the US it is a teaspoon and a half per cup plus a quarter teaspoon of salt. Whisk it right through the dry flour before anything wet goes near it, because baking powder sitting in one spot gives a cake one big hole and a flat edge.
Is self-rising flour the same as self-raising flour?
Almost, but not on salt. UK self-raising flour has none in it, and US self-rising flour has about a quarter teaspoon a cup. Put UK self-raising into an American recipe and add that salt yourself. Put US self-rising into a British recipe and leave the salt the recipe asks for out.
Can I turn self-raising flour back into plain flour?
No, and nothing you do at home will get the baking powder out. Use the self-raising flour as it is and leave out the recipe's own raising agent instead: 300 g of self-raising already carries about four teaspoons of baking powder. For pastry or anything with no raising agent at all, buy plain flour.
What happens if I use plain flour instead of cake flour?
The cake works, and it comes out slightly denser and chewier. Plain flour sits about three percentage points higher on protein, which is enough to notice in a light sponge and not enough to ruin one. Mix as little as you can once the flour is in, and if there is cornflour in the cupboard the swap takes a minute.
Can I use plain flour instead of bread flour?
Yes. The loaf will be softer and less chewy, which for most home bread is fine. Plain flour is 10 to 12 percent protein against 12 to 14 for strong bread flour. If you keep vital wheat gluten, a teaspoon per cup closes the gap: 500 g of bread flour becomes 488 g of plain flour and 4 teaspoons of gluten, about 12 g.
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