How to scale a recipe based on one ingredient

When one ingredient determines how much you can make, use that ingredient to calculate the scale factor for everything else.

1. Find the amount the recipe requires

Example: the recipe calls for 500 g flour.

2. Measure what you have

Suppose you have 327 g.

3. Divide available by required

327 ÷ 500 = 0.654. That means you can make 65.4% of the original batch.

4. Multiply every quantified ingredient by 0.654

300 g sugar becomes about 196 g. 200 g butter becomes about 131 g. Three eggs become about 1.96 eggs.

5. Review ingredients that do not scale neatly

Eggs, salt, spices and leavening may need practical judgment. For an awkward fractional egg, beating it first can make proportional use easier.

What if more than one ingredient is limited?

Use Use What I Have. It compares each available/required ratio and automatically uses the smallest one.