Self-Raising Flour Calculator
Calculate how much baking powder to add to plain flour to make self-raising flour. Free self-raising flour calculator. Works for any amount of flour needed.
UK Self-Raising Flour
Sift together thoroughly before using. Ratio: 2 level tsp baking powder per 150g plain flour.
Quick Reference Table
How to use this tool
Enter your plain flour quantity
Type the amount of plain flour in grams (or click a quick amount button). The baking powder quantity updates instantly.
Read the baking powder amount
The result shows baking powder in both grams (for scale users) and teaspoons (for spoon users). Both are given because kitchen scales and measuring spoons have different precision levels.
Mix thoroughly before using
Sift the plain flour and baking powder together at least twice — or whisk in a bowl for 30 seconds. Uneven distribution causes patches of over-risen and flat bake.
Tips
Always sift self-raising flour (shop-bought or homemade) before measuring — baking powder can compact and clump during storage.
Homemade self-raising flour is best used immediately. The baking powder begins reacting slowly once mixed with the flour, especially in humid conditions.
Old baking powder loses potency. Test by dropping a teaspoon into hot water — it should bubble vigorously. Replace baking powder every 6–12 months.
For wholemeal self-raising flour: use the same ratio (8g baking powder per 150g) but expect denser results. Adding an extra ½ tsp helps compensate for the heavier bran.
About this self-raising flour calculator tool
Self-raising flour is simply plain flour pre-mixed with baking powder. The standard UK ratio is 8g of baking powder per 150g of plain flour (approximately 2 level teaspoons). This matches the leavening level in most UK self-raising flour brands and works well for sponge cakes, scones, muffins, and most everyday baking.
Making your own self-raising flour is practical when you've run out, when you want to control the leavening level precisely, or when a recipe calls for a specific amount that doesn't conveniently align with shop-bought quantities. The formula is linear — scale the baking powder proportionally to the flour weight.
The leavening level can be adjusted for specific recipes. Light, airy cakes (Victoria sponge, chiffon cake) often use the standard 8g per 150g. Denser bakes like banana bread or carrot cake may use less. Scones typically use a higher ratio — up to 10–12g per 150g — for their characteristic open crumb. This calculator uses the standard UK ratio, which is correct for the vast majority of recipes.
Baking powder quality matters. Old or poorly stored baking powder (moisture exposure causes it to activate prematurely) will under-leaven your bake. Test by dropping a teaspoon into hot water — vigorous bubbling means it is still active. Most baking powder has a shelf life of 12–18 months; replace it annually if you bake regularly.
Frequently asked questions
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