Recipe Scaling Calculator
Enter how many servings the recipe makes, how many you want, and up to four ingredient amounts. Every amount is scaled by the same factor.
Scale Factor
1.5 ×
Ingredient 1 Scaled
3
Ingredient 2 Scaled
2.25
Ingredient 3 Scaled
1.13
Ingredient 4 Scaled
4.5
How it works
Scaling a recipe is a single ratio. Divide the number of servings you want by the number the recipe makes to get a scale factor, then multiply every ingredient by that factor. Doubling a recipe is a scale factor of 2; halving it is 0.5.
Enter each ingredient in whatever unit the recipe uses. The calculator does not care whether it is cups, grams, tablespoons or eggs: the scaled amount comes back in the same unit, so 2 cups becomes 3 cups and 200 g becomes 300 g.
Scaled amounts are shown to two decimal places. For eggs or whole items, round to the nearest whole one; for small quantities of salt, spices or leavening, see the assumptions below.
Formula
scale factor = desired servings ÷ original servings scaled amount = original amount × scale factor
Example
A recipe written for 4 servings that you want to stretch to 6 has a scale factor of 6 ÷ 4 = 1.5.
Multiplying each ingredient by 1.5: 2 cups of flour becomes 3 cups, 1.5 cups of milk becomes 2.25 cups, 0.75 cup of sugar becomes 1.125 cups (shown as 1.13, which is 1⅛ cups), and 3 eggs become 4.5, which in practice means rounding to 4 or 5.
Assumptions and limitations
- Every ingredient scales in direct proportion to the servings. This is true for most ingredients, but salt, spices, strong flavourings and chemical leavening (baking soda, baking powder) are often best scaled a little less than proportionally when a recipe is doubled or more. Taste and adjust.
- Cooking time and temperature do not scale with the ingredients. A larger batch in a bigger pan may need longer; a larger batch in the same pan will be deeper and may need longer still, or a lower temperature.
- Pan and pot sizes are not calculated. A recipe scaled by 1.5 needs about 1.5 times the pan area for the same depth.
- Servings may be fractional (for example 2.5), which is useful when scaling by portion weight rather than head count.
- Amounts are shown to two decimal places; the calculation itself is not rounded.
Frequently asked questions
Why are there only four ingredient rows?
The form has a fixed set of four amount fields; it cannot add rows. For a recipe with more ingredients, note the scale factor and multiply the rest yourself, or run the calculator again with the next four amounts. The scale factor is the same for every ingredient, so it only needs to be worked out once.
Can I scale a recipe by weight instead of servings?
Yes. Enter the original and desired weights in place of servings. A 500 g batch of dough scaled to 750 g uses exactly the same arithmetic as 4 servings scaled to 6, and gives the same 1.5 scale factor.
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