How recipe scaling works
Every ingredient in a recipe is a proportion of the whole. To make more or less, you multiply each amount by the same number, called the scale factor. Get the factor by dividing the servings you want by the servings the recipe makes. The scaler reads the number at the start of each line, multiplies it, and rounds the result to a fraction you can actually measure.
The formula
new amount = original amount × scale factor
1 1/2 = 1 + 1 ÷ 2 = 1.5
Results under 10 are shown to the nearest 1/8 or 1/3. Larger whole-number amounts, like 250 g of butter, are shown as plain numbers, and amounts you typed as decimals stay as decimals.
Example: a recipe for 4, made for 6
The factor is 6 ÷ 4 = 1.5. Here is the default ingredient list scaled:
| Original | × 1.5 | Scaled |
|---|---|---|
| 2 cups all-purpose flour | 3 | 3 cups |
| 1 1/2 tsp baking powder | 2.25 | 2 1/4 tsp |
| ½ tsp salt | 0.75 | 3/4 tsp |
| ⅔ cup sugar | 1 | 1 cup |
| 2 eggs | 3 | 3 eggs |
| 1 1/4 cups milk | 1.875 | 1 7/8 cups |
| 3 tbsp melted butter | 4.5 | 4 1/2 tbsp |
| Pinch of nutmeg | — | Pinch of nutmeg (unchanged) |
1 7/8 cups is 1 3/4 cups plus 2 tablespoons, and 4 1/2 tablespoons is 1/4 cup plus 1/2 tablespoon.
Tips for scaling recipes
- Convert awkward amounts. 16 tablespoons = 1 cup and 3 teaspoons = 1 tablespoon, so 6 tbsp is easier to measure as 1/4 cup + 2 tbsp.
- Weigh for big batches. Cup measures drift as quantities grow. Converting to grams first keeps 3x and 4x batches accurate.
- Rethink the pan. A scaled cake needs a pan with the matching area. Our pan size converter does that math.
- Season to taste. Salt, chili and strong spices are worth adding gradually when you scale up a lot.
- Watch the clock, not the math. Cooking time doesn't scale with the factor. Check doneness rather than multiplying the time.
Frequently asked questions
How do I scale a recipe?
Divide the servings you want by the servings the recipe makes to get a scale factor, then multiply every ingredient by it. A recipe for 4 that you want to serve 6 has a factor of 6 ÷ 4 = 1.5, so 2 cups of flour becomes 3 cups.
What fractions does the scaler understand?
Whole numbers (3), decimals (1.5), simple fractions (3/4), mixed numbers (1 1/2), Unicode fractions (½, ¼, ¾, ⅓, ⅔, ⅛) and ranges (2-3). The number has to be at the start of the line. Lines without a leading number, like 'salt to taste', are copied over unchanged.
How do I scale eggs?
Round to the nearest whole egg for most recipes. If you need half an egg, beat one egg and use about half of it, roughly 2 tablespoons, since a large egg is about 3 1/2 tablespoons out of the shell. In baking, a scale is the most accurate way: a large egg without its shell weighs about 50 grams.
Can I just double the baking time when I double a recipe?
No. Baking time depends mostly on how deep the food is, not how much there is. If you double a cake recipe and bake it in two pans of the original size, the time stays about the same. If you use one bigger, deeper pan, it takes longer, so start checking at the original time and keep going in 5 minute steps.
Do spices and leavening scale the same way?
Usually close enough for small changes like 1.5x or 2x. For big jumps (4x and up), many cooks scale salt, strong spices and baking soda a little less, then taste and adjust. Weighing ingredients in grams makes large batches much more predictable.
Rates and figures last checked October 2026.
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