Halve, double or triple a recipe
Tap a factor and the scaler above rewrites every line. Each button is the whole recipe times that number — here's what it does to ¾ cup sugar:
Doubling is where people hit surprises — pans, bake times and leavening each follow their own rule. The guide to doubling a recipe walks through each one with the math done.
How to Scale a Recipe Up or Down Without Ruining It
Scaling a recipe sounds like simple multiplication — and mostly it is. The scale factor is your target yield divided by the recipe's yield: doubling a 4-serving recipe to 8 means multiplying every ingredient by 2; taking a 12-cookie batch down to 8 cookies means multiplying by ⅔. This recipe scaler applies the factor to your whole ingredient list at once, understands mixed numbers ("2 1/2"), unicode fractions ("¾"), and decimals, and rewrites the result using fractions you can actually measure.
The hard parts are the edge cases, and the tool handles those too. Fractional eggs get flagged with a practical fix. Lines with no quantity ("pinch of salt") pass through untouched. And scaling beyond 3× triggers a warning. The math stays exact; the warning is there because a recipe is only tested at its written size, and a bowl holding several batches is harder to mix evenly. Our advice is to mix in rounds of 3× or less, or bake a test batch and adjust salt, spices and leavening to taste. The 3× line is our own convention, not a published standard.
Common scale factors at a glance
| You want to… | Factor | 1 cup becomes |
|---|---|---|
| Halve a recipe | × 0.5 | ½ cup |
| Take 12 servings down to 8 | × 0.667 | ⅔ cup |
| Take 4 servings to 6 (or 8 to 12) | × 1.5 | 1½ cups |
| Double it | × 2 | 2 cups |
| Take 4 servings to 10 | × 2.5 | 2½ cups |
| Triple it | × 3 | 3 cups |
One thing multiplication can't fix: geometry. If you double a cake recipe but keep the same pan, the batter sits twice as deep and will not bake in the same time. When your scaling changes pans, use our cake pan converter to get the right pan size, temperature, and timing together. And if you'd rather scale by weight — the more reliable way — convert your cups to grams first and multiply the gram figures.