Recipe Scaling Calculator
Scale any recipe to the number of servings you actually want — with the scaling factor applied to an ingredient, and a note on what does not scale linearly.
The scaling factor is simply new servings ÷ original servings, and most ingredients follow it exactly.
How the recipe scaling calculator works
The scaling factor is simply new servings ÷ original servings, and most ingredients follow it exactly. Three things do not. Salt and strong spices scale slightly behind the factor, because seasoning is judged against the whole dish rather than each portion. Baking time barely changes when a recipe is doubled into a wider tin but changes a great deal when it is doubled into a deeper one, since heat travels from the outside in. And raizing agents in a large batch can outpace the oven, so a doubled cake often wants a slightly cooler, longer bake.
Formula: factor = new servings ÷ original servings; scaled = amount × factor
Worked examples
| Inputs | Scaled amount | Note |
|---|---|---|
| A recipe for 4, serving 6 | 375 | ×1.5 — 375 |
| Halving a recipe for 8 | 250 | ×0.5 — 250 |
| A dinner party — 4 up to 12 | 600 | ×3, and worth checking the tin size |
FAQFrequently 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.
Does salt scale the same way?
Not quite. Seasoning is judged against the whole dish, so a tripled recipe usually wants a little under triple the salt — season towards the end and taste.
Does cooking time scale?
Much less than the quantity. A wider tin cooks in nearly the same time; a deeper one takes considerably longer, because heat has further to travel.
Can I scale baking recipes freely?
Up to about double, yes. Beyond that raizing agents, tin geometry and oven capacity all start to matter, and the result is not simply a bigger cake.
What about eggs?
They come in whole units. Round to the nearest egg and adjust the liquid slightly, or weigh them — a large egg is about 50 g out of shell.
Where these figures come from
- US FDA — Safe Minimum Internal Temperatures — the internal temperatures the roasting calculator targets
- NIST SP 811 — Guide for the Use of the International System of Units — the exact weight and volume conversions used throughout
- US Food and Drug Administration — food safety and labelling standards
Last checked: September 2026. Baking ratios follow standard baker's percentage practice; roasting guidance follows published safe internal temperatures.