Proven Pantry kitchen tools
Baking pan size converter
Have an 8-inch pan and a recipe written for a 9-inch pan? Compare the base areas and find how much of each ingredient to use.
Baking pan converter
Use the inside dimensions of straight-sided pans. This scales ingredients to keep a similar batter depth.
63.62 in² total base area
50.27 in² total base area
Multiply each ingredient by
0.7901×
Use 79.01% of the original recipe.
Scale an ingredient
From 500 g, new quantity:
Keep the recipe’s doneness cues. This does not calculate baking time or adjust for pan material. Fractional eggs need care; a tested recipe for your pan can be easier.
Shared links include the inputs shown here.
How the calculation works
The factor is your pans’ total base area divided by the recipe’s total base area. A round pan’s area is π × (diameter ÷ 2)². A square or rectangular pan’s area is width × length. Multiply by the number of pans before comparing.
Scaling by base area aims to preserve batter depth. It assumes straight sides and suitable pan depth. It does not establish the usable capacity of a tapered loaf pan, Bundt pan, or decorative mold.
| Recipe pan | Your pan | Recipe amount |
|---|---|---|
| 9-inch round | 8-inch round | 79.01% |
| 8-inch square | 9-inch round | 99.40% |
| Two 8-inch rounds | 9 × 13-inch rectangle | 116.38% |
What about baking time?
Do not multiply the baking time by the recipe factor. Pan depth, batter type, oven conditions, and pan material all matter. Keep enough room for rising batter, check the recipe’s doneness cues, and use a recipe tested for your pan when the substitution is a large change.
Sources and further reading
The geometric calculations are our own. These baking references explain when pan substitutions make sense: