Cooking for more, or fewer, people
A recipe that serves four is perfect until six guests show up, or until you want to cook for one. Scaling a recipe is simple arithmetic, but a few ingredients, such as eggs and spices, and a different pan size need more thought. This calculator multiplies each ingredient, rounds the eggs and compares pan sizes.
The scale factor
Scale factor = servings you want ÷ servings in the recipe.
Multiply every ingredient by that factor. Halving a recipe gives a factor of 0.5, doubling gives 2.
Worked example: from 4 to 6 servings
- Factor: 6 ÷ 4 = 1.5.
- Flour: 2 cups × 1.5 = 3 cups.
- Sugar: 3/4 cup × 1.5 = 1 1/8 cups (1.13 cups).
- Butter: 8 tablespoons × 1.5 = 12 tablespoons, or 3/4 cup.
- Eggs: 2 × 1.5 = 3 eggs.
If you switch from an 8-inch to a 9-inch round pan at the same time, the area ratio is (9 ÷ 8)² = 1.27: the larger pan needs about 27 percent more batter to come out the same thickness.
Scale factor by servings
| Servings | Factor | Flour | Eggs |
|---|---|---|---|
| 2 | 0.50 | 1 cup | 1 |
| 4 | 1.00 | 2 cups | 2 |
| 6 | 1.50 | 3 cups | 3 |
| 8 | 2.00 | 4 cups | 4 |
| 12 | 3.00 | 6 cups | 6 |
Handling awkward amounts
- Eggs. When the result falls between whole eggs, beat one egg and add part of it. A large egg is about 3 tablespoons beaten, so a quarter egg is about 2 1/4 teaspoons and a half egg about 1 1/2 tablespoons.
- Small measures. 1 tablespoon = 3 teaspoons, 1/4 cup = 4 tablespoons, 1 cup = 16 tablespoons. Converting 0.375 cup to 6 tablespoons is easier than finding 3/8 on a measuring cup.
- Weigh when you can. Scaling grams on a kitchen scale avoids rounding errors in cups.
What not to scale blindly
- Salt, spices and chili. Increase them a little less than the factor, then taste and adjust. Flavors can become overpowering when a recipe is tripled.
- Baking powder and baking soda. For large increases, many bakers scale leavening slightly below the factor to avoid a bitter taste and a collapsing crumb.
- Baking time. Time depends on the depth of batter and the size of the dish, not the quantity of ingredients. A larger pan with the same depth bakes in about the same time; a deeper one takes longer at a slightly lower temperature.
- Pan size. Doubling a cake recipe does not mean doubling the pan’s diameter: a 12-inch round has 2.25 times the area of an 8-inch round, so a doubled recipe in a 12-inch pan comes out a little thinner than the original.
Pan areas at a glance
An 8-inch round pan has about 50 square inches, a 9-inch round about 64, an 8-inch square 64 and a 9 by 13 inch pan 117. That makes a 9-inch round and an 8-inch square interchangeable, and a 9 by 13 pan close to twice an 8-inch square.