Resize a recipe

What this tool does that the others do not

Scaling a recipe is more than one multiplication. You may want a different number of servings, or the same recipe in another pan, and in both cases the final question is what to put on the scale. The recipe scaler multiplies by servings, the cake pan converter works out the area ratio between pans, and the cups to grams converter converts one ingredient. The resizer does the three in one pass: it takes either a servings change or a pan change as the factor, applies it to every line of your recipe, writes the result in kitchen fractions, and adds the new weight in grams for the ingredients it recognizes (about 52 common ones).

The method

By servings: factor = servings you want ÷ servings the recipe makes. By pan: factor = area of the new pan bottom ÷ area of the old one. A round pan has area π × (diameter ÷ 2)², a square pan side × side and a rectangular pan length × width. Every amount is multiplied by the factor; cups, tablespoons and teaspoons are converted into the handiest measure (⅛ cup becomes 2 tablespoons) and written as the nearest ⅛ or ⅓. The weight is the new volume multiplied by the grams per teaspoon of that ingredient, taken from the King Arthur Baking Ingredient Weight Chart (for example 120 g per cup of all-purpose flour, 198 g of granulated sugar, 227 g of milk or water, a large egg 50 g).

A worked example

A recipe written for a 9 × 13 inch pan, baked instead in one 9-inch round: the areas are 117 and 63.6 square inches, so the factor is 0.544, about 54%. A recipe for four, cooked for six, is ×1.5. In that case 2 cups of all-purpose flour become 3 cups, which is 360 g against 240 g, and 1 egg becomes 1 ½ eggs, which is 75 g: one whole egg plus half of a beaten one. For a ×4 batch the straight multiple of 1½ teaspoons of baking powder is 2 tbsp; with the large-batch adjustment it is 1 ½ tbsp, and ⅛ teaspoon of ground cloves, which would be ½ tsp in a straight multiple, becomes ⅓ tsp.

What does not scale in a straight line

Leavening and seasoning. The Culinary Institute of America advises, when scaling up, to start leaveners such as baking powder and yeast at about 75 percent of the calculated amount and flavorings at about two-thirds, then to test with a trial batch. It gives the warning that a tripled cake with baking powder multiplied by three could rise over the pan, and that ⅛ teaspoon of cloves multiplied by four could overpower a cookie. The adjustment is optional on this page and it only applies when the factor is above 1; the CIA’s examples are tripled and quadrupled recipes, so leave it off for a small change.

Time and temperature. The CIA also says a different batch size may call for a different baking time. The area ratio assumes the same depth of batter; if you spread the same amount over a bigger pan it will bake faster. Watch it and test for doneness.

Eggs and other whole units. The factor often gives half an egg or a fraction of a can. Weigh the egg, or round the recipe to whole units and adjust the liquid. Rounding to the nearest ⅛ means every number is a kitchen-ready fraction, not exact.

Weights are for typical ingredients. The King Arthur table is for their own flour and the way they scoop and weigh; another brand, a humid kitchen, or packed measuring can change the weight by several percent.

Common questions

How do I convert a recipe to a different pan size?

Compare the areas of the pan bottoms and multiply the recipe by the ratio. A 9 × 13 inch pan has 117 square inches; a 9-inch round has 63.6, so the round pan takes 0.544 of the batter (about 54%). An 8-inch round is 50.3 square inches and a 10-inch round 78.5, so the larger pan needs 1.56 times the batter.

Can I use the same batter depth in a different pan?

That is the idea behind the area ratio: if the batter fills the new pan to the same depth, the baking time is roughly unchanged. If you use a deeper or shallower layer, the time and the best oven temperature change, so start testing early. Note that this assumes the same pan sides, since a pan with high sides or a dark finish behaves differently.

What should I do with half an egg?

Weigh it. A large egg is 50 grams in the King Arthur table, so 1½ eggs is 75 grams: whisk one egg, pour into a bowl on a scale and take what you need. The resizer shows the weight in the last column for that reason.

Do baking powder and spices scale in a straight line?

For small changes, close enough. For large ones, no: the Culinary Institute of America advises starting leavening at about 75 percent of the straight multiple, and flavorings at about two-thirds, when you scale a recipe up, then tasting and testing. The reason it gives is that multiplying baking powder by three in a tripled cake could make the batter rise over the pan. Turn on the large-batch adjustment to see those amounts.

How do I convert cups to grams for a recipe?

Multiply the number of cups by the weight of one cup of that ingredient. King Arthur lists 120 grams for a cup of all-purpose flour, 198 for granulated sugar, 227 for water or milk, 213 for packed brown sugar and 113 for a half cup (one stick) of butter. The calculator matches the ingredient names in your list to its table of about fifty items and gives the new weight, which is far more repeatable than measuring cups.

Does the baking time change when I double a recipe?

Only if the batter gets deeper or the oven gets crowded. Two pans baked side by side take about the original time; one bigger pan takes longer. The CIA’s advice is to run a test batch when you change the size, and to judge doneness by sight, a toothpick or temperature, not the clock.

Baking above 3,500 feet? Use the high altitude baking calculator. Working in baker’s percentages? See the baker’s percentage calculator. Feeding a crowd? The party food calculator gives amounts per guest.

Sources, read October 27, 2026: King Arthur Baking, Ingredient Weight Chart (kingarthurbaking.com/learn/ingredient-weight-chart; weights in grams per measure); Culinary Institute of America, “Scaling Baking Recipes Up and Down” (CIA Foodies; leavening at about 75 percent and flavorings at about two-thirds of the calculated amount when scaling up, trial batch and baking-time advice). Spoon and cup sizes: NIST, Handbook 44, Appendix C. How we check our calculators.