How to Scale a Recipe Up or Down Without Ruining It

Doubling a recipe is easy. Turning a recipe for 6 into one for 4, or 8 into 15, needs a scaling factor, plus a few cook's rules the math alone won't tell you.

Find the scaling factor

Then multiply every ingredient by the factor. Going from 6 servings to 4 gives 4 ÷ 6 ≈ 0.667, so 300 g of flour becomes 200 g and 3 eggs become 2.

Work in weight when you can

Weights scale cleanly; cups and spoons are fiddlier. Two thirds of 3/4 cup is 1/2 cup, which is easy, but two thirds of 1 tablespoon is 2 teaspoons, which only helps once you know that 1 tablespoon = 3 teaspoons (US). If a recipe gives grams, use them.

Handy kitchen equivalents (US)

• 1 cup = 16 tablespoons
• 1 tablespoon = 3 teaspoons
• 1 cup ≈ 240 ml
• 1 ounce ≈ 28 g

Adjusting the pan size

For baking, scale by pan area, not just servings. The area of a round pan is π × radius². A 9-inch round pan (about 64 sq in) holds about 1.27 times as much batter as an 8-inch pan (about 50 sq in).

Ingredients that don't scale neatly

• Salt, spices and chili: scale up slightly less than the factor, then taste and adjust.
• Leavening (baking powder, yeast): for big batches, many bakers use a little less than the exact scaled amount.
• Eggs: round to the nearest whole egg, or beat one and use part of it by weight (a large egg is about 50 g without the shell).
• Liquids in braises and soups: evaporation doesn't double when the recipe does, so start with less liquid and add more as needed.

Cooking time and temperature

Keep the oven temperature the same. A bigger or deeper dish needs more time; smaller portions need less. Check early, and use a thermometer for meat.