Recipe Scaler
Scaling a recipe is mostly multiplication, with a handful of important exceptions. This calculator handles the arithmetic; the notes below cover what it cannot.
Formula
New amount = original amount × (desired servings ÷ original servings)
- Ingredients scale linearly; cooking time and tin size do not
- Raising agents, salt and strong spices often need less than the factor
A 4-serving recipe for 6: factor 1.5, so 200 g of flour becomes 300 g
The Scaling Factor
Factor = Desired servings ÷ Original servings
Taking a recipe for 4 up to 6 gives a factor of 1.5, so 300 g of flour becomes 450 g.
Multiply every ingredient by the same factor. Working in weights rather than cups makes awkward factors far easier — two thirds of 175 g is straightforward, two thirds of three quarters of a cup is not.
What Does Not Scale Linearly
- Salt and spices: scale to about three quarters of the factor and adjust to taste. Doubling chilli often overwhelms a dish.
- Raising agents: baking powder and bicarbonate rarely scale cleanly. Doubling can give a bitter, over-risen result.
- Alcohol and extracts: concentrated flavours intensify disproportionately.
- Thickeners: scale with the liquid, not the servings.
Time, Temperature and Pan Size
Cooking time does not scale with quantity. A double batch in the same tin is deeper, so it needs longer at a slightly lower temperature; spread across two tins, the time barely changes.
Match the pan to the volume: the same cake mixture in a larger tin bakes faster and drier. And remember eggs come in whole units — for a factor of 1.5 on three eggs, beat four and use four fifths, or round to the nearest sensible number.
Quick Reference
| From | To | Factor | Also adjust |
|---|---|---|---|
| 4 | 2 | 0.5 | Use a smaller tin; reduce time slightly |
| 4 | 6 | 1.5 | Tin area, not just depth |
| 4 | 8 | 2.0 | Two tins beat one deep one |
| 4 | 12 | 3.0 | Cook in batches; pans crowd and steam |
Frequently Asked Questions
- How do I scale a recipe?
- Divide the servings you want by the servings it makes, then multiply every ingredient by that factor. Weights scale more cleanly than cups.
- Do I double the cooking time for a double batch?
- No. Time depends on depth and pan size rather than total quantity. A deeper tin needs longer at a slightly lower temperature; two tins need barely any extra.
- Which ingredients should not be doubled?
- Salt, spices, raising agents, alcohol and extracts. Scale these to around three quarters of the factor and adjust to taste.
- How do I handle half an egg?
- Beat a whole egg and weigh out the fraction you need, roughly 50 g per egg. Or round the recipe to a factor that gives whole eggs.