How to Scale a Recipe Up or Down

To make more or fewer servings, multiply every ingredient by the same scale factor: the new number of servings divided by the old. Recipes are full of fractions, so this is fraction multiplication in the kitchen.

For learning and kitchen practice. Cup weights are typical values, not exact. For doneness, use a food thermometer and safe internal temperatures, not cooking time alone.

Try it with your own problem ↓

The steps

Scale factor = new servings ÷ old servings. Simplify it (6/4 = 3/2 = 1 1/2).
Multiply each amount by the factor. Change mixed numbers to improper fractions first.
Simplify each answer, and turn improper fractions back into mixed numbers.
Change awkward amounts into ones you can measure: 3 tsp = 1 tbsp, and 16 tbsp = 1 cup.
Round things that come whole, like eggs, sensibly, and think about the pan size and baking time.

A worked example

A recipe for 4 servings uses 2 cups flour, 3/4 tsp salt, 2/3 cup milk and 2 eggs. Scale it to 6 servings.

Factor: 6 ÷ 4 = 6/4 = 3/2 = 1 1/2.
Flour: 2 × 3/2 = 3 cups.
Salt: 3/4 × 3/2 = 9/8 = 1 1/8 tsp.
Milk: 2/3 × 3/2 = 6/6 = 1 cup.
Eggs: 2 × 3/2 = 3 eggs.

For 6 servings: 3 cups flour, 1 1/8 tsp salt, 1 cup milk and 3 eggs.

Why it works

Each serving needs the same amount of every ingredient, so if you make 1 1/2 times as many servings, every amount has to be 1 1/2 times as big. Multiplying everything by one factor keeps the ratios between the ingredients the same, and the ratios are what make it the same recipe.

Try it with your own problem

Open The Recipe Card (free) with this example already filled in. It shows every step, and you can type over it with your own numbers.

Work it out: 4 servings to 6: 2 cups flour, 3/4 tsp salt, 2/3 cup milk, 2 eggsOpens The Recipe Card with this example

Or try these

More cooking and baking math, every step written out: open The Recipe Card.

Common mistakes

Adding instead of multiplying. Going from 4 to 6 servings is not “add 2 to everything”. It is × 1 1/2.
Flipping the factor. It is new ÷ old. 4 ÷ 6 would shrink the recipe.
Multiplying a mixed number in pieces. 1 1/2 × 2/3 is 3/2 × 2/3 = 1. Change it to an improper fraction first.
Scaling the baking time. A bigger batch needs a bigger pan, and the time doesn’t grow by the factor. Check for doneness.

Questions people ask

How do I halve 3/4 cup?

3/4 × 1/2 = 3/8 cup, which is 6 tablespoons (3/8 × 16).

How do I triple 2/3 cup of sugar?

2/3 × 3 = 6/3 = 2 cups.

Does this work for yeast and salt in bread?

For small changes, scale everything the same way. For big batches, bakers weigh the ingredients and use baker’s percentages.

Keep learning

Show The Steps is free, with no accounts or ads, and everything is worked out in your own browser. Start at the home page.