Baking guides

Scaling recipes and converting pan sizes

Most scaling is one multiplication. The trouble comes from choosing the wrong multiplier, usually when a recipe moves to a different pan, and from the few ingredients and steps that don't scale cleanly. This guide covers the three ways to get the multiplier, a pan area table, and what to watch for.

Last reviewed: 2026-10-25

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Three ways to find the multiplier

1. By yield

Divide what you want by what the recipe makes. A recipe for 12 rolls scaled to 30 rolls has a multiplier of 30 ÷ 12 = 2.5, so every ingredient is multiplied by 2.5. This works whenever the pieces stay the same size.

2. By dough weight, with baker's percentages

When you need a set amount of dough, add up the formula's baker's percentages and divide the target weight by that total. Take a roll dough of 100% flour, 65% water, 2% salt and 1.2% yeast. The percentages add up to 168.2%. Twelve 80 g rolls need 960 g of dough, so the flour is 960 ÷ 1.682 = 570.7 g. The other ingredients follow from the flour: water 371.0 g, salt 11.4 g and yeast 6.8 g, 959.9 g in all.

King Arthur Baking calls the result of this division the formula conversion factor. In its French bread example the percentages total 168.25% and the bakery wants 150 lb of dough: 150 ÷ 168.25 = 0.8915, which King Arthur rounds up to 0.9 because a little extra dough is better than coming up short. In practice you also add a little for dough left in the bowl and for bake loss; the bake loss calculator handles the second.

3. By pan area

For cakes, brownies, focaccia and anything else that fills a pan, the batter or dough should keep the same depth in the new pan. If the depth stays the same, the amount needed is proportional to the pan's floor area, so the multiplier is new area ÷ old area.

Working out pan area

• Round pan: π × radius², where the radius is half the diameter. A 9-inch round is 3.1416 × 4.5² = 63.6 square inches.
• Square or rectangular pan: length × width. A 9 × 13-inch pan is 117 square inches.
• Measure across the inside top edge. Pans with sloped sides hold a little less than the top measurement suggests, so for close work measure the base too and use the average.

Worked conversions

• 8-inch round to 9-inch round: 63.6 ÷ 50.3 = 1.27. One extra inch of diameter needs 27% more batter, not 12.5%. Going the other way, 9-inch to 8-inch, multiply by 0.79.
• 9-inch round to 8 × 8-inch square: 64 ÷ 63.6 = 1.006. They are effectively the same, so the recipe moves over unchanged.
• Two 9-inch rounds (a layer cake) into one 9 × 13-inch pan: 117 ÷ (2 × 63.6) = 0.92. The sheet pan holds about 8% less batter at the same depth, so either scale down slightly or accept a slightly deeper cake and a longer bake.
• 20 cm round to 26 cm round: 531 ÷ 314 = 1.69. A recipe with 200 g of flour needs about 338 g.
• 24 cm round to a 23 × 33 cm tray: 759 ÷ 452 = 1.68.

Rule to remember: area grows with the square of the diameter. Doubling a round pan's diameter needs four times the batter.

Depth, time and temperature

The area method assumes the batter stays at the same depth. If you keep the recipe the same and move it to a smaller pan, the layer gets deeper. A deeper cake takes longer to bake through, and its outside can overbake before the middle sets. Baking time does not scale in proportion to the amount of batter. It depends on how thick the layer is and how far heat has to travel to the centre, so a doubled recipe in two pans bakes in about the original time, while the same doubled recipe in one deep pan takes much longer. Start checking early with a skewer or a thermometer and write down the time that worked for the next bake. For bread, time depends on the size of each loaf, not on how many loaves are in the batch.

Ingredients that need care

Yeast in large bread batches

Multiplying is the right starting point. In large batches many bakers trim the yeast a little, because a large mass of dough holds heat and can ferment faster. The batch scaling calculator shows an adjusted yeast figure above 2x, using a published rule of thumb (the full amount up to 3x, about 90% above that). It is not a measured standard, so treat it as a first test. Controlling dough temperature with the dough temperature calculator does more for consistent fermentation.

Salt

Salt stays at its baker's percentage at every batch size. If the original dough has 2% salt, the big batch has 2% salt too. In King Arthur Baking's ciabatta example, the 1.8% salt in the formula becomes 0.9 lb when the dough is scaled to 50 lb of flour, the same percentage at a much larger size.

Eggs

A multiplier of 2.5 asks for 2.5 eggs. Beat the eggs together and weigh out the share you need instead of rounding to a whole egg, which can change a small recipe noticeably.

Mixer capacity

Check your mixer's rated dough capacity before scaling up. An overloaded mixer kneads poorly and warms the dough more, which shifts your friction factor and your fermentation times. Two batches are often better than one oversized batch.

A scaling checklist

1. Work out the multiplier by yield, dough weight or pan area.
2. Multiply every ingredient by weight, not volume.
3. Keep salt at the same percentage; treat any yeast reduction as a test.
4. Check mixer capacity and pan sizes before you weigh anything.
5. Expect the bake time to change if the depth or piece size changes, and note what worked.

For the notation behind method 2, see baker's percentages explained. To cost the scaled batch, use the recipe cost calculator.

Frequently asked questions

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