How to use the recipe scaler
- Choose how to scale. With Servings, enter how many servings the recipe makes and how many you want. With A multiplier, enter a number such as 2, 0.5 or 1/3.
- Replace the example ingredients with your own. For each one, type the amount (2, 1/2, 1 1/2 or 0.75), pick the unit, and type the name. Use Add an ingredient for more rows, up to 40.
- Leave Switch to a larger or smaller unit ticked if you want 12 teaspoons to read as 1/4 cup, and choose whether to round to eighths, quarters or decimals.
- Read the scaled table. Use Copy, Print or CSV to take it into the kitchen. An ingredient with no amount, such as pepper, is listed as "as needed".
Formula
Scale factor = servings wanted / servings the recipe makes
Scaled amount = original amount x scale factor (exact fractions)
1 tablespoon = 3 teaspoons, 1 cup = 16 tablespoons = 48 teaspoons
1 pound = 16 ounces, 1 kilogram = 1,000 grams, 1 liter = 1,000 milliliters
Amounts are kept as exact fractions until the last step, so thirds do not pick up rounding error. The result is then shown to the nearest eighth, quarter or decimal you chose.
From 4 servings to 6
The factor is 6 / 4 = 3/2. The example recipe has 1 1/2 cups flour, which becomes 1 1/2 x 3/2 = 9/4 cups, shown as 2 1/4 cups. Two tablespoons of butter become 3 tablespoons, 1 teaspoon of salt becomes 1 1/2 teaspoons, 3 eggs become 4 1/2 and 500 g of potatoes become 750 g.
Going from 3 servings to 5 gives a factor of 5/3. One cup of milk becomes 5/3 cup, which is 1.6667 cups. The nearest eighth is 1 5/8 cups, because 1 5/8 is 1.625 and 1 3/4 is 1.75. Rounding to quarters instead gives 1 3/4 cups.
Units and kitchen fractions
US volume units are linked by exact definitions, so the tool can move between teaspoons, tablespoons and cups. With the larger-unit option on, amounts under 3 teaspoons stay in teaspoons, amounts from 3 teaspoons up to 1/4 cup are shown in tablespoons, and 1/4 cup or more is shown in cups. Pounds, ounces, grams, kilograms, liters and milliliters follow the same idea within their own families.
Fluid ounces, pints, quarts and gallons form a separate family, and weights in ounces are never mixed with volumes. Cup measures of flour, sugar and similar ingredients are volumes, so a conversion to grams needs the cooking measurement converter and the ingredient, which this tool does not guess.
Where straight scaling goes wrong
Multiplying every amount by the same number is the right starting point, but a recipe is more than its ingredients. Baking and cooking times, the size of the pan, the amount of salt and strong spices, and leavening such as baking powder do not always change in the same proportion. A double batch of cake batter in one deep pan bakes differently from two normal pans.
The tool warns when the change is very large, more than eight times bigger or smaller than the original. For ratios of flour, water and other ingredients, see the baker's percentage calculator, and for feeding a crowd, the party food and drink calculator.
Assumptions and limits
- Amounts are US customary and metric measures with the exact relations listed above. Nothing is converted between volume and weight.
- The example ingredients are only an example. Replace them with your own recipe.
- Amounts must be plain numbers or fractions. Ranges such as 2 to 3 and words such as "a handful" are not understood, so leave the amount blank for those and the line is listed as "as needed".
- Very small results round to "a pinch", which is a description rather than a measurement.
Frequently asked questions
How do I double a recipe?
Choose the multiplier option and enter 2, or choose servings and enter double the original number. To halve a recipe use 0.5 or 1/2.
Can I type amounts like 1 1/2 or 1/3?
Yes. Whole numbers, fractions, mixed numbers with a space or hyphen, and decimals are all read. The tool also understands the single-character fractions such as one half and three quarters.
Why did 12 teaspoons turn into 1/4 cup?
That is the larger-unit option. Twelve teaspoons is the same amount as four tablespoons or a quarter cup, and the tool shows the unit that reads best. Untick the option to keep your original unit.
Is the recipe I type saved or sent anywhere?
No. Everything is calculated in your browser. Ingredient names are not even included in share links, so a link you send carries only the numbers.