How it scales
By servings, every amount is multiplied by the servings you want divided by the servings the recipe makes: from 8 to 12 is × 1.5.
By pan size, it compares the pans’ areas, for a cake or tray bake of the same depth. A round pan’s area is π × radius², a square one’s is side × side and a rectangle’s is width × length, so going from a 20 cm round pan to a 24 cm one is × 1.44, not × 1.2. Sizes can be in centimetres or inches: the factor is the same.
By a number, everything is multiplied by it: 0.5 halves the recipe, 3 makes three batches.
Pan sizes compared
How much more batter a bigger pan of the same depth takes:
| Pan in the recipe | Your pan | Multiply by |
|---|---|---|
| Round, 20 cm | Round, 24 cm | × 1.44 |
| Round, 18 cm | Round, 23 cm | × 1.63 |
| Round, 8 in | Round, 9 in | × 1.27 |
| Round, 8 in | Round, 10 in | × 1.56 |
| Round, 20 cm | Square, 20 cm | × 1.27 |
| Square, 20 cm | Rectangle, 20 × 30 cm | × 1.5 |
| Square, 8 in | Rectangle, 9 × 13 in | × 1.83 |
Converting units
Amounts can be shown as written, in metric (grams, kilos, millilitres, litres) or in US units (ounces, pounds, spoons and cups). The conversions it uses:
| 1 oz | 28.35 g |
| 1 lb | 453.6 g |
| 1 tsp | 5 ml |
| 1 tbsp | 15 ml |
| 1 cup (US) | 236.6 ml |
| 1 cup (metric) | 250 ml |
| 1 fl oz (US) | 29.57 ml |
Cups and spoons measure volume, and grams weight, so the scaler never turns one into the other: a cup of flour weighs much less than a cup of sugar. To go from cups to grams, weigh a cupful of that ingredient once.
Tips for scaling a recipe
Weigh rather than measure by the cup when you scale up: small errors grow with the batch. Round eggs to whole ones, or beat them and weigh the share you need (an average egg is about 50 g out of its shell). Raising agents, salt and spices can usually be scaled as they are for a batch up to about three times the size; test bigger jumps first. A bigger or deeper pan needs a lower oven or a longer bake, so check early.
Questions
How do I scale a recipe to a different pan size?
Compare the areas of the pans: for round pans, divide the square of the new diameter by the square of the old one. From 20 cm to 24 cm is 576 ÷ 400 = 1.44, so multiply every ingredient by 1.44. Choose “Pan size” in the calculator to do it for any shape.
Can it convert cups to grams?
No, because a cup measures volume and the weight depends on the ingredient: a cup of flour and a cup of sugar weigh very different amounts. It converts cups to millilitres, and ounces to grams.
How do I halve a recipe with 3 eggs?
Half is 1.5 eggs: use one egg, then beat a second and add half of it, about 25 g. For larger batches, weigh the eggs out of their shells.
Does the baking time change when I scale a recipe?
Yes, it changes with the depth of the batter more than with the amount. The same depth in a bigger pan bakes in about the same time; a deeper one takes longer and may need a slightly lower oven.
Is what I type saved or sent anywhere?
It is kept in your browser on this device, so it’s still there when you come back, and it is never sent to us or anyone else. The calculator works entirely on your device. “Clear all” removes it.