Enter the servings the recipe makes, the servings you want and the ingredient amount. The scale factor is the desired servings divided by the original servings, and every ingredient is multiplied by it. Convert mixed numbers to decimals first, such as 1.5 for a cup and a half.
Weigh ingredients in grams where possible, since scaling by weight is more accurate than by volume.
Recipe Scaling: worked example
| Servings in the recipe | 4 |
|---|---|
| Servings you want | 10 |
| Ingredient amount in the recipe | 1.5 |
| Scaled ingredient amount | 3.8 |
| Scale factor | 2.50× |
Recipe Scaling: formula
NIST Handbook 44: Units and Systems of Measurement · OpenStax Prealgebra: ratios and proportions
Baked goods are chemistry, so large changes in scale can fail, especially leavening and eggs. Whole eggs are hard to divide, and one egg can be beaten and measured by weight. Reactions and evaporation depend on the surface of the pan.
Halving is often easier than an odd factor.
Common error: Scaling salt, leavening and strong spices at the full factor. Taste them in steps, because they often need less than the multiplier suggests.
Recipe Scaling: changing Ingredient amount in the recipe
| Ingredient amount in the recipe | Scaled ingredient amount | Scale factor |
|---|---|---|
| 1.2 | 3 | 2.50× |
| 1.4 | 3.4 | 2.50× |
| 1.5 (example) | 3.8 | 2.50× |
| 1.7 | 4.1 | 2.50× |
| 1.8 | 4.5 | 2.50× |
Recipe Scaling: compare input ranges
| Input | Tested from | To | Scaled ingredient amount: low input | Scaled ingredient amount: high input | Swing |
|---|---|---|---|---|---|
| Servings in the recipe | 3 | 5 | 5 | 3 | 2 (53%) |
| Servings you want | 9 | 11 | 3.4 | 4.1 | 0.75 (20%) |
| Ingredient amount in the recipe | 1.4 | 1.7 | 3.4 | 4.1 | 0.75 (20%) |
Recipe Scaling: individual input comparisons
| Input | Value | Scaled ingredient amount | Scale factor |
|---|---|---|---|
| Servings in the recipe | 2 | 7.5 | 5.00× |
| 3 | 5 | 3.33× | |
| 4 | 3.8 | 2.50× | |
| 5 | 3 | 2.00× | |
| 6 | 2.5 | 1.67× | |
| Servings you want | 8 | 3 | 2.00× |
| 9 | 3.4 | 2.25× | |
| 10 | 3.8 | 2.50× | |
| 11 | 4.1 | 2.75× | |
| 12 | 4.5 | 3.00× | |
| Ingredient amount in the recipe | 1.2 | 3 | 2.50× |
| 1.4 | 3.4 | 2.50× | |
| 1.5 | 3.8 | 2.50× | |
| 1.7 | 4.1 | 2.50× | |
| 1.8 | 4.5 | 2.50× |
Recipe Scaling: combined input changes
| Ingredient amount in the recipe / Servings in the recipe | 2 | 4 | 6 |
|---|---|---|---|
| 1.2 | 6 | 3 | 2 |
| 1.4 | 6.8 | 3.4 | 2.3 |
| 1.5 | 7.5 | 3.8 | 2.5 |
| 1.7 | 8.3 | 4.1 | 2.8 |
| 1.8 | 9 | 4.5 | 3 |
Recipe Scaling: which assumptions move the result?
Recipe Scaling: values and definitions
| Quantity and definition | Value used |
|---|---|
| Servings in the recipe | 4 |
| Servings you want | 10 |
| Ingredient amount in the recipe — Any unit: cups, grams, teaspoons. The result comes back in the same unit. | 1.5 |
| Scaled ingredient amount | 3.8 |
| Scale factor | 2.50× |
Recipe Scaling: half and double Servings in the recipe
| Servings in the recipe | Scaled ingredient amount |
|---|---|
| 2 | 7.5 |
| 4 | 3.8 |
| 8 | 1.9 |
Cooking & Kitchen calculators: Baking Pan Size Calculator, Coffee to Water Ratio Calculator, Recipe Cost Per Serving Calculator.
Scaling one ingredient is a single multiplication: the servings you want divided by the servings in the recipe. Ten servings from a recipe for four is a factor of 2.5, so 1.5 cups becomes 3.75. The arithmetic is easy.
What goes wrong is everything that does not scale in a straight line, such as spices, salt, baking time and pan size.
Scale the pan and the time separately. A larger batch in the same pan changes depth, and depth is what decides how long it bakes.
Adjust the pan on the baking pan size calculator, cost it on the recipe cost per serving calculator and check brewing ratios on the coffee ratio calculator. The fraction and proportion calculators help with the arithmetic, and the cooking measurement converters change cups, ounces and grams.
Does a 2.5 recipe factor multiply cooking time by 2.5?
No. Time depends on geometry, temperature and method, not a direct serving-count multiplier. Scaling ingredient amounts establishes quantities for the chosen serving factor.
It does not establish heat transfer or doneness for a different pan or batch.
Can I multiply a fractional ingredient amount?
Yes. Enter 1.5 for one and a half units; the default factor returns 3.75 of the same units.
How do I double a recipe correctly?
Multiply every ingredient by two, but scale spices, salt and leavening more cautiously and adjust the pan size and cooking time.
Do baking times change when I scale a recipe?
Yes. Larger amounts or deeper pans take longer, so watch for doneness rather than using the original time.
How do I scale a recipe by weight?
Weigh the ingredients in grams and multiply each by the scale factor, which avoids errors from packing and measuring cups.