How to use this calculator
Choose a target serving count, or choose Available ingredients to find the largest proportional batch your checked supplies support. Enter up to 20 original ingredient amounts and units. In stock mode, enter available quantities in those same units; leave unchecked supplies blank. The smallest available-to-required ratio sets the batch. Zero available stock for a required ingredient means no positive batch. Copy the result or save a worksheet with the checked supplies.
Try an available-ingredients example
See which checked supply limits the batch and what is left. Opening this example replaces the current inputs.
The formula
A worked example
Scaling a 6-serving recipe to 10 servings gives a multiplier of 1.6667. An ingredient listed as 300 g becomes 500 g. For a 12-serving recipe requiring 600 g flour and 240 g butter, 375 g flour supports 0.625× but 120 g butter supports only 0.5×. Butter limits the batch to 6 serving equivalents: 300 g flour and 120 g butter, leaving 75 g flour.
Assumptions & limitations
Scales ingredient amounts proportionally. Stock left blank is not checked, and zero original quantities do not constrain the batch. Serving equivalents can be fractional; this does not guarantee that many identical individual items. Cooking time, pan geometry, evaporation, spices, and leavening may require adjustment. It does not convert volume to mass, suggest substitutes, or round indivisible items such as eggs. Stock mode can scale above one original batch when entered supplies allow it.
Common questions
Can I scale down a recipe?
Yes. A target below the original serving count, or limited stock, can produce a factor below 1.
What does blank available stock mean?
It means that supply has not been checked. Enter zero when you know you have none. The maximum batch is conditional on every unchecked supply being sufficient.
What if two ingredients run out together?
Both are listed as limiting when their ratios match within calculation precision.
Do I multiply the cooking time too?
No. Cooking time rarely changes in direct proportion to the number of servings. Check doneness appropriately.
Supporting reference
The method above states this calculator’s assumptions. This reference provides related definitions and technical context.
King Arthur Baking: baker’s percentage ↗Formula and worked example checked against automated test cases. About our methodology.