One cup of cake flour weighs 120 g, spooned and levelled, according to King Arthur Baking. Cake flour is the finest, softest flour in the kitchen — milled from soft wheat, with the lowest protein content of any wheat flour — and it is what gives sponge cakes their tender, fine crumb. The cup weight of 120 g is the same as all-purpose flour, which surprises many bakers, but the two flours behave very differently: cake flour's low protein means less gluten, and less gluten means a softer cake. This guide covers the weight, the measurement, the substitutes, and the recipes where cake flour earns its keep. All weights on this page are approximate; finely milled cake flour is sometimes quoted at 100 g per cup when sifted, so spoon and level rather than scooping, and verify with a scale when precision matters.
Cake Flour: weight and measurement table
The table below gives the weight of cake flour in every measure you will use, from a teaspoon up to 2 cups, all derived from the King Arthur Baking figure of 120 g per cup, spooned and levelled. Every figure is approximate — spooned and levelled is a technique, not a machine setting — so when the recipe matters, weigh the ingredient on a kitchen scale instead.
| Amount | Weight (approx.) |
| --- | --- |
| 1 teaspoon | 2.5 g |
| 1 tablespoon | 7.5 g |
| 1/4 cup (4 tbsp) | 30 g |
| 1/3 cup | 40 g |
| 1/2 cup (8 tbsp) | 60 g |
| 3/4 cup (12 tbsp) | 90 g |
| 1 cup (16 tbsp) | 120 g |
| 2 cups | 240 g |
| 100 g | 0.8 cups |
There are 3 teaspoons in a tablespoon and 16 tablespoons in a cup, so you can move between any of these measures by multiplying or dividing. If a recipe calls for 100 g and you only have measuring cups, that is about 0.8 cups. Keep the cups to grams converter open while you cook and you will never need to do the arithmetic in your head.
What is Cake Flour?
Cake flour is very finely milled, low-protein flour that gives cakes a tender, fine crumb. It is made from soft wheat, with a protein content of about 7 to 9 percent, against all-purpose flour's 10 to 12 percent. That low protein is the point: less protein means less gluten, and less gluten means a cake that is soft and delicate instead of tough and chewy. The flour is also bleached, which weakens the protein further and helps the flour absorb more liquid and sugar — a bleached cake flour can hold more sugar and more liquid than all-purpose flour, which is why professional cake recipes use it. It is used for sponge cakes, chiffon and delicate layer cakes, and it is the flour that makes the difference between a good sponge and a great one. It keeps for up to 1 year in an airtight container in a cool, dry place.
How to measure Cake Flour correctly
Cake Flour is measured spooned and levelled, and the method matters more than most cooks realise. For dry ingredients, spoon the ingredient into the measure with a smaller spoon, letting it fall loosely, then sweep a knife across the top to level it — never dip the measuring cup into the bag, because dipping compresses the ingredient and adds up to 20 percent. For liquids, pour into a liquid measuring jug and read the level at eye height, or weigh directly into the bowl, which is the most accurate method of all. The King Arthur Baking figure used on this page is 120 g per cup, and it is the figure the site's converters use, so the numbers here and the numbers in the tool always agree. Confidence in this figure is high.
A note on the published figures
King Arthur lists 120 g per cup; finely milled cake flour is sometimes quoted at 100 g per cup when sifted, so spoon and level rather than scooping.
Worked examples
A chiffon cake for a celebration
A chiffon cake uses 2 cups of cake flour — 240 g — sifted with sugar, baking powder and salt, then folded with whipped egg whites. The weight matters because chiffon is a foam cake: the flour must be light enough to stay suspended in the egg white foam, and cake flour's fine milling and low protein are what make that possible. Weighing 240 g keeps the ratio exact — a cup too much and the cake is dense and heavy, a cup too little and it collapses. The flour is sifted twice, once on its own and once with the dry ingredients, which aerates it and removes any lumps. The cake is baked in an ungreased tube pan, because the batter needs to grip the sides to climb.
A white layer cake
A white layer cake uses 3 cups of cake flour — 360 g — creamed with butter and sugar for a fine, white crumb. The weight is critical because the cake's tenderness depends on the flour's low protein: 360 g of cake flour gives a crumb so fine it almost melts, while the same weight of all-purpose flour gives a noticeably tougher cake. Weighing the flour also lets you scale the recipe — a single layer needs 180 g, and a triple layer needs 540 g — and the cake is baked until a skewer comes out clean, about 25 minutes for a 20 cm tin. The cake is cooled completely before frosting, because a warm cake melts the buttercream.
A strawberry shortcake
A strawberry shortcake uses 1.5 cups of cake flour — about 180 g — in a biscuit dough that is rolled, cut and baked until golden. The weight matters because shortcake sits between cake and biscuit: it needs to be tender enough to split and fill with cream, but firm enough to hold its shape. Cake flour's low protein gives that tenderness, and weighing 180 g keeps the dough's ratio exact. The dough is handled as little as possible — overworking it develops the gluten that cake flour is meant to avoid — and the biscuits are baked for 12 minutes, until the tops are golden and the middles are still soft.
Tenderness and the fine crumb
Cake flour's job is tenderness, and it achieves it in two ways: low protein and fine milling. The low protein — 7 to 9 percent against all-purpose flour's 10 to 12 — means less gluten forms when the flour meets liquid, so the crumb stays soft and delicate instead of turning tough. The fine milling means the flour particles are smaller and more uniform, so they absorb liquid evenly and produce a crumb with a finer, more even texture. Together, those two qualities are what make a sponge cake feel like it dissolves on the tongue. But cake flour's tenderness is also its limitation: it cannot support a heavy cake. A fruit cake or a carrot cake made with cake flour will collapse, because the flour has no strength to hold the weight of the fruit and nuts. Cake flour is for light, delicate cakes — sponge, chiffon, white layer cake — and for those it is unmatched. For anything heavier, use all-purpose flour. And when you substitute, do it by weight: 1 cup of cake flour is 120 g, and the standard substitute is 3/4 cup plus 2 tablespoons of all-purpose flour with 2 tablespoons of cornstarch, which mimics cake flour's low protein.
What to use instead
If you run out of cake flour, these are the tested substitutes from our substitution data, with the ratio and the case where each one does not work. Use the ratio by weight where it is given, and check the warning before you commit the batter.
- Cake flour to All-purpose flour: 3/4 cup + 2 tbsp all-purpose flour per cup of cake flour. Do not swap flours 1:1 in delicate cakes or yeasted breads without adjusting liquid and expecting a different crumb.
The golden rule for any substitution is to match the job, not just the ingredient: a substitute that works in a sauce may fail in a cake, because the two recipes ask different things of the ingredient. When in doubt, use a recipe written for the substitute rather than adapting one written for the original.
Storage
Airtight container, cool and dry, up to 1 year. That is the headline, but the details matter. Store cake flour in an airtight container, away from heat, light and strong smells — dry ingredients absorb odours readily, and a bag of flour stored next to the spices will taste of them within a week. Label the container with the date you opened it, so you know how long it has been there, and check it before you bake: if it smells off, tastes bitter, or shows any sign of moisture or insects, discard it. Buying in smaller quantities and using it promptly is better than buying in bulk and storing it for a year, because every ingredient loses flavour with time, even the ones that never truly go bad.
Frequently asked questions
How many grams is 1 cup of cake flour?
One cup of cake flour weighs 120 g, spooned and levelled, according to King Arthur Baking. Finely milled cake flour is sometimes quoted at 100 g per cup when sifted, so spoon and level rather than scooping. One tablespoon weighs 7.5 g.
How many cups of cake flour are in 500 g?
There are about 4.2 cups in 500 g of cake flour (500 divided by 120 is 4.2 cups). A standard 500 g bag holds just over 4 cups.
Can I use all-purpose flour instead of cake flour?
Yes, with an adjustment. For each cup of cake flour, use 3/4 cup plus 2 tablespoons of all-purpose flour with 2 tablespoons of cornstarch. The cornstarch dilutes the protein and mimics cake flour's tenderness. The result will be very close, though not quite as fine.
What is the difference between cake flour and pastry flour?
Cake flour has less protein (7 to 9 percent) than pastry flour (about 9 to 10 percent) and is more finely milled. Cake flour is for sponge and chiffon cakes; pastry flour is for pie crusts, tarts and biscuits, where a little more strength is needed. They weigh almost the same per cup but behave differently.
How long does cake flour last?
Up to 1 year in an airtight container in a cool, dry place. Discard it if it smells musty or tastes bitter. Cake flour absorbs odours easily, so keep it sealed and away from strong smells.
Related pages
If you cook with this ingredient regularly, these pages will help: the cups to grams converter for any amount, the ingredient density lookup for the full table of 120 ingredients, the Cake Flour cups to grams page for cup conversions, the Cake Flour grams to cups page for working backwards from grams, and the Cake Flour tablespoons to grams page for spoon measures. You may also want All-Purpose Flour, Bread Flour.