Recipe Scaler
Scale any recipe up or down instantly. Handles fractions, mixed numbers, and ranges.
How It Works
Each ingredient line is parsed for a leading quantity — whole numbers, fractions like 1/2, mixed numbers like 1 1/2, unicode fractions like ½ and ⅓, decimals, and ranges like 2-3. The
quantity is multiplied by the ratio of desired to original servings, then converted
back to the nearest common fraction (⅛, ¼, ⅓, ½, ⅔, ¾…) for readability. Lines with
no leading number — like "salt to taste" — are passed through unchanged.
Baking caveat: leavening agents (baking powder, baking soda, yeast) and salt don't always scale linearly. When doubling a recipe, use a little less than double the baking powder — start at 1.75× and adjust to taste. Mixing and baking times may also need adjustment when changing pan sizes.
Tips for scaling baking recipes: Egg quantities can't always be halved (use two yolks in place of one whole egg when halving), and pan dimensions scale by area rather than by volume. A recipe for a 9-inch round pan doesn't just double when you move to a 13×9 inch pan — the area increases by about 2×, but depth matters too.
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Frequently Asked Questions
How do I scale a recipe up or down?
Divide the desired serving count by the original serving count to get the scaling factor, then multiply each ingredient quantity by that factor. Example: scaling a 4-serving recipe to 10 servings → factor = 10 ÷ 4 = 2.5. Enter the original and desired servings above and all quantities are scaled automatically.
Do leavening agents scale linearly?
No. Baking powder, baking soda, and yeast do not scale proportionally. When doubling a recipe, use about 1.75× the leavening (not 2×). When tripling, use about 2.5×. Too much leavening causes collapse or a metallic taste; too little results in dense baked goods.
How do I scale a recipe to a different pan size?
Calculate the areas of both pans and multiply by the factor. A 9-inch round pan has area π×4.5² ≈ 63.6 sq in. A 9×13-inch pan has area 117 sq in. Factor = 117 ÷ 63.6 ≈ 1.84. Scale ingredients by 1.84×, but baking time may need adjustment — check doneness earlier.
What is the difference between a US cup and a metric cup?
A US cup = 236.6 ml. A metric cup (used in Australia and Canada) = 250 ml. This difference (~6%) matters in baking. This calculator scales quantities as given — verify which cup your recipe uses.