How to convert a recipe to a different pan
Compare the base of the two pans. Batter fills a pan from the bottom up, so a pan with half the base holds half the recipe at the same depth. The converter divides the area of your pan by the area of the recipe’s pan and gives you the number to multiply every ingredient by.
For a square or rectangular pan the area is length times width. For a round pan it is 3.14 times the radius squared, which is why a 9 inch round pan holds about the same as an 8 inch square one.
Baking pan sizes and their areas
| Pan | Base in square inches | Base in cm² |
|---|---|---|
| 8 inch round | 50 | 324 |
| 9 inch round | 64 | 410 |
| 10 inch round | 79 | 507 |
| 8 x 8 inch square | 64 | 413 |
| 9 x 9 inch square | 81 | 523 |
| 11 x 7 inch | 77 | 497 |
| 9 x 13 inch | 117 | 755 |
| 10 x 15 inch jelly roll | 150 | 968 |
| 13 x 18 inch half sheet | 234 | 1510 |
| 8 1/2 x 4 1/2 inch loaf | 38 | 247 |
| 9 x 5 inch loaf | 45 | 290 |
| 20 cm round | 49 | 314 |
| 23 cm round | 64 | 415 |
| 20 cm square | 62 | 400 |
| 20 x 30 cm | 93 | 600 |
Common pan swaps
| Recipe’s pan | Your pan | Multiply by | In practice |
|---|---|---|---|
| 9 x 13 inch | 8 x 8 inch square | 0.55 | Half the recipe |
| 8 x 8 inch square | 9 x 13 inch | 1.83 | A double recipe, slightly thinner |
| 9 x 13 inch | 9 x 9 inch square | 0.69 | Two thirds of the recipe |
| 9 inch round | 8 x 8 inch square | 1.01 | The recipe as it is |
| 8 inch round | 9 inch round | 1.27 | One and a quarter times the recipe |
| 9 inch round | 8 inch round | 0.79 | Three quarters of the recipe |
| 9 x 5 inch loaf | 8 1/2 x 4 1/2 inch loaf | 0.85 | The recipe as it is, a little taller |
| 9 x 13 inch | 13 x 18 inch half sheet | 2.00 | A double recipe |
When the number is close to a simple fraction, use the fraction: nobody needs 0.55 of a recipe when half of it fits. Then scale the ingredients with the recipe scaler.
Depth and baking time
The conversion keeps the batter at the same depth, so the baking time stays close to the original. If you pour a full recipe into a smaller pan the layer is deeper and takes longer, and it may overflow: fill a pan no more than two thirds. If the layer is thinner it bakes faster. In both cases keep the oven temperature and start checking early.
Inches and centimeters
A 20 cm round tin is close to an 8 inch pan and a 23 cm tin is close to a 9 inch pan. A 20 by 30 cm tin sits between an 11 by 7 inch and a 9 by 13 inch pan.
