How do I scale my recipe?
Type how many servings the recipe makes, how many you want, and each ingredient. The recipe scaler multiplies every amount by the same factor and shows the result in kitchen fractions, with small cup amounts also in spoons.
- Scale factor
- 1 1/2
Multiply each amount by 1 1/2 for 6 servings.
- Scale factor (decimal)
- 1.5
- Scaled ingredients
- 3 3/8 cups flour; 1 1/2 tsp baking soda; 1 1/8 cups sugar; 3/4 cup butter; 3 eggs
Scale factor: 1 1/2. Multiply each amount by 1 1/2 for 6 servings.
How to calculate
Scales every ingredient of a recipe from one number of servings to another, in exact fractions, with small cup amounts also in tablespoons and teaspoons.
Example with the default inputs (Recipe makes (servings) 4, Servings you want 6, Ingredients [Amount 2 1/4, Unit cup, Ingredient (optional) flour; Amount 1, Unit tsp, Ingredient (optional) baking soda; Amount 3/4, Unit cup, Ingredient (optional) sugar; Amount 1/2, Unit cup, Ingredient (optional) butter; Amount 2, Unit whole (count), Ingredient (optional) eggs]): Multiply each amount by 1 1/2 for 6 servings.
Method: Scale factor = servings you want ÷ servings the recipe makes; each new amount = amount × scale factor, in the same unit.
- Every ingredient scales by the same factor. Baking times, pan sizes, and strong flavours such as salt and spices may need judgment when you scale a lot.
- Amounts keep their unit. A cup amount under 1/4 cup also shows in tablespoons (1 cup = 16 tbsp), and a tablespoon amount under 1 also shows in teaspoons (1 tbsp = 3 tsp), US customary.
- Amounts with a denominator up to 16 show as fractions; others show as a decimal with 2 places.
Worked examples
Each example is checked against the calculator on every build.
- Recipe makes (servings) 4, Servings you want 6, Ingredients 2 1/4 cup flour; 1 tsp baking soda; 3/4 cup sugar; 1/2 cup butter; 2 whole (count) eggs gives Scale factor (decimal) 1.5, Scaled ingredients 3 3/8 cups flour; 1 1/2 tsp baking soda; 1 1/8 cups sugar; 3/4 cup butter; 3 eggs.Source: NIST Handbook 44 (2026), Appendix C, General Tables of Units of Measurement (1 cup = 8 fl oz; 1 tablespoon = 1/2 fl oz; 1 teaspoon = 1/6 fl oz), https://www.nist.gov/document/2026-nist-handbook-44-appendix-c
- Recipe makes (servings) 12, Servings you want 3, Ingredients 1/2 cup milk; 1 tbsp oil; 250 g flour gives Scale factor (decimal) 0.25, Scaled ingredients 1/8 cup milk (2 tbsp); 1/4 tbsp oil (3/4 tsp); 62 1/2 g flour.Source: NIST Handbook 44 (2026), Appendix C, General Tables of Units of Measurement (1 cup = 8 fl oz; 1 tablespoon = 1/2 fl oz; 1 teaspoon = 1/6 fl oz), https://www.nist.gov/document/2026-nist-handbook-44-appendix-c
- Recipe makes (servings) 6, Servings you want 7, Ingredients 1 cup rice; 0.5 L stock gives Scale factor (decimal) 1.166667, Scaled ingredients 1 1/6 cups rice; 7/12 L stock.Source: USDA FoodData Central (household measures: cup, tablespoon, teaspoon portions of foods), https://fdc.nal.usda.gov/
- Recipe makes (servings) 3, Servings you want 10, Ingredients 1 tsp salt gives Scaled ingredients 3 1/3 tsp salt.Source: NIST Handbook 44 (2026), Appendix C, General Tables of Units of Measurement (1 cup = 8 fl oz; 1 tablespoon = 1/2 fl oz; 1 teaspoon = 1/6 fl oz), https://www.nist.gov/document/2026-nist-handbook-44-appendix-c
- Recipe makes (servings) 20, Servings you want 3, Ingredients 1 cup water gives Scaled ingredients about 0.15 cup water (2 2/5 tbsp).Source: NIST Handbook 44 (2026), Appendix C, General Tables of Units of Measurement (1 cup = 8 fl oz; 1 tablespoon = 1/2 fl oz; 1 teaspoon = 1/6 fl oz), https://www.nist.gov/document/2026-nist-handbook-44-appendix-c
How it works
- Scale factor = servings you want ÷ servings the recipe makes.
- New amount = amount × scale factor, in the same unit.
All the arithmetic is exact: each amount, and both serving counts, are used as the exact numbers you typed.
How amounts show. An amount whose fraction, in lowest terms, has a denominator of 16 or less shows as a whole or mixed number (3 3/8). Any other amount shows as “about” a decimal with up to 2 places, rounded half up from its exact value, trailing zeros dropped (about 0.15). Cup amounts over 1 say “cups”; other units are written as chosen, and “whole” shows just the number and the name.
Spoons for small amounts. A cup amount under 1/4 cup also shows in tablespoons (× 16), and a tablespoon amount under 1 also shows in teaspoons (× 3), in brackets, by the same display rule. 1 cup = 16 tbsp and 1 tbsp = 3 tsp follow from NIST’s US customary measures (8, 1/2 and 1/6 fluid ounce).
Output format. The scale factor shows as a fraction in lowest terms (a mixed number when over 1) and as a decimal with up to 4 places. The scaled list is “amount unit name” per ingredient, joined by semicolons.
Rules
- Servings from 0.1 to 10,000. From 1 to 30 ingredients.
- An amount is a whole number, a decimal (2.5, .5), a fraction (3/4) or a mixed number (1 1/2), from 0 to 100,000. Anything else, or a denominator of 0, gives no answer, with a message naming the row.
Worked examples by hand
From 4 servings to 6. Factor 6 ÷ 4 = 3/2. 2 1/4 cups × 3/2 = 27/8 = 3 3/8 cups flour; 1 tsp → 1 1/2 tsp baking soda; 3/4 cup → 1 1/8 cups sugar; 1/2 cup → 3/4 cup butter; 2 eggs → 3 eggs.
From 12 servings to 3. Factor 1/4. 1/2 cup → 1/8 cup milk = 2 tbsp; 1 tbsp → 1/4 tbsp oil = 3/4 tsp; 250 g → 62 1/2 g flour.
From 6 servings to 7. Factor 7/6. 1 cup → 1 1/6 cups rice; 0.5 L → 7/12 L stock.
From 3 servings to 10. Factor 10/3. 1 tsp → 3 1/3 tsp salt.
From 20 servings to 3. Factor 3/20. 1 cup → 3/20 cup, about 0.15 cup water = 48/20 = 2 2/5 tbsp.
Other questions people ask
How do I scale a recipe?
Divide the servings you want by the servings the recipe makes to get the scale factor, then multiply every ingredient by it. From 4 servings to 6 the factor is 6 ÷ 4 = 1 1/2, so 2 1/4 cups of flour become 3 3/8 cups.
How do I halve or double a recipe?
To double, the factor is 2; to halve, 1/2. Type the recipe’s servings and twice or half as many, or type 1 and 2 (or 2 and 1) to scale by 2 or 1/2 directly.
How many tablespoons are in a cup?
16 tablespoons are in 1 cup, and 3 teaspoons are in 1 tablespoon (US customary measures). So 1/8 cup is 2 tablespoons, and 1/4 tablespoon is 3/4 teaspoon. The scaler shows these for small amounts.
Why do some amounts show as “about” a decimal?
Fractions with a denominator up to 16 (halves, thirds, quarters, eighths, sixteenths, and so on) show exactly. Others, such as 3/20 cup, show as a decimal to 2 places, 0.15, because no measuring cup marks them.
Does everything scale the same way?
The arithmetic does, but cooking does not always. Baking times, pan sizes, leavening, salt and spices may need judgment when you scale by a lot. Eggs may need rounding to a whole egg.
Can I type decimals and mixed numbers?
Yes. Type 2, 0.5, 3/4 or 1 1/2 (a space before the fraction). The page works with the exact values you type.