COOKING & BAKING / NO. 012 FREE ONLINE TOOL

Recipe
scaler.

Resize a recipe by servings, by a simple multiplier, or to fit a different pan. Type quantities the way recipes write them (1 1/2, ¾) and get amounts you can actually measure.

01 / YOUR INPUTSUPDATES AS YOU TYPE

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02 / YOUR RESULT LIVE
CALCULATED ANSWER
—

HOW IT WAS CALCULATED
THE EXPLANATION / 01

Bigger, smaller,
still delicious.

THE RULES WE USE
  • Every quantity is multiplied by the same scale factor.
  • Servings: factor = servings needed ÷ servings the recipe makes.
  • Pan size: factor = area of your pan ÷ area of the recipe pan. Round pans use π × diameter² ÷ 4. This keeps the batter at the same depth.
  • Cup, spoon, ounce, pound and count amounts are shown as kitchen fractions to the nearest ⅛ (never more than 5% off), with the exact value alongside.
  • Units are kept as you entered them. Nothing is converted between volume and weight.

How do you scale a recipe?

Divide the number of servings you want by the number the recipe makes, then multiply every ingredient by that factor. A recipe for 4 that you want to serve 6 has a factor of 6 ÷ 4 = 1.5, so 2¼ cups of flour becomes 3⅜ cups and 2 eggs become 3.

factor = servings needed ÷ recipe servings
new amount = original amount × factor

How do you adjust a recipe for a different pan?

Compare the areas of the two pans, not their diameters. A 9-inch round pan has an area of about 63.6 square inches and an 8-inch round pan about 50.3, so moving from 8 to 9 inches needs 1.27 times the batter, not 1.125. A useful coincidence: a 9-inch round pan and an 8-inch square pan hold almost the same amount.

Scaling by area keeps the batter at the same depth. Deeper or shallower batter bakes differently, so check doneness early when you change pans.

round pan area = π × diameter² ÷ 4
rectangular pan area = length × width
factor = new pan area ÷ recipe pan area

What doesn't scale in a straight line?

Ingredient amounts scale, but some other things do not. Baking times and temperatures depend on the size and depth of what is in the oven, so a doubled cake in a bigger pan may need a different time. Pot size changes how quickly liquids evaporate. Many cooks also add salt, strong spices and chili gradually when scaling up a lot, then taste. Treat these as cooking judgement: the calculator does not change them for you.

What about half an egg?

Eggs come whole. When a scaled recipe calls for part of an egg, beat the eggs together and measure the portion you need, or round to a whole egg and adjust the other liquids slightly. The calculator flags any ingredient line with eggs that no longer comes out to a whole number.

WORKED EXAMPLES / 02EACH ONE IS CHECKED BY OUR TEST SUITE

Worked examples.

01

From 4 to 6 servings

A cookie recipe for 4 uses 2¼ cups flour, ¾ cup sugar and 2 large eggs. Scale it to 6.

× 1.5: 3⅜ cups flour, 1⅛ cups sugar and 3 eggs.

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02

Halving a recipe

Halve a recipe with 1½ cups milk and 3 eggs.

¾ cup milk and 1½ eggs (beat the eggs and use half).

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03

An 8-inch round recipe in a 9-inch pan

A cake recipe is written for an 8-inch round pan, but you have a 9-inch round pan.

× 1.27 (exactly 81/64): make about 27% more batter.

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04

A 9 × 13 recipe in an 8-inch square pan

A brownie recipe for a 9 × 13 inch pan, made in an 8 × 8 inch pan.

× 0.547: use a little over half of each ingredient.

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05

A 9-inch round recipe in an 8-inch square pan

Will a 9-inch round cake recipe fit an 8-inch square pan?

Yes: × 1.006, almost exactly the same area.

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LIMITS / 03

What this calculator
does not do.

  • It does not change cooking times, oven temperatures or pan depth. Check doneness early.
  • It does not convert between cups and grams. Use the cooking converter for volume units and the milligrams-to-teaspoons calculator to turn weights into spoons with an ingredient’s density.
  • Pan sizes are inside dimensions at the base. Sloped sides and very different depths change the result.
  • Kitchen fractions are rounded to the nearest ⅛. For baking that depends on precise ratios, weigh ingredients.
QUESTIONS / 04SHORT ANSWERS

Common questions.

How do I double a recipe?

Choose “A multiplier” and enter 2, or set servings needed to twice the original.

Can I type fractions?

Yes: 3/4, 1 1/2, 1½ and decimals like 1.5 all work.

Do I double the baking time when I double a recipe?

Usually not. Time depends on the depth and size of the pan more than on the total amount. Check early and test for doneness.

Can I share my scaled recipe?

Yes. Your ingredient list is kept in the page address, so “Copy link to these inputs” shares the whole recipe.

SOURCES & METHOD / 05REVIEWED NOVEMBER 2026
  1. NIST SP 811, Appendix B.8 — US cup, tablespoon and teaspoon definitions

Scaling is a single multiplication per ingredient; pan factors use exact area formulas. Tests cover servings, multipliers, round and rectangular pans, fraction parsing (1/2, 1 1/2, ½, 1½, decimals with a comma), invalid quantities, blank rows, kitchen-fraction rounding limits and the partial-egg flag.