Baking Pan Converter
Scale a recipe between round and rectangular pans, in inches or centimetres, including multiple pans.
How the pan conversion works
A round pan has base area π × diameter² ÷ 4. A rectangular pan has base area length × width. Measurements in inches are multiplied by 2.54 before areas are compared. Because the ratio uses area, it keeps the same intended batter depth in each pan. Multiply each ingredient in the original recipe by the result.
Worked examples
Moving from one 8-inch round pan to one 9-inch round pan gives 9² ÷ 8² = 1.265625. A recipe with 250 g flour therefore becomes about 316.4 g flour. The same multiplier applies to the other ingredients.
Moving from a 9 × 13-inch rectangular pan to two 8-inch round pans gives (2 × π × 4²) ÷ (9 × 13), or about 0.8592×. The two round pans together have a smaller base area than the original rectangle.
Measure the inside of the pan
Use the inside bottom diameter or inside bottom length and width. Handles and wide rims are not part of the batter area. This tool treats pans as straight-sided shapes; sloping sides, decorative moulds, tube pans and Bundt pans need a capacity comparison instead. Check that the pan walls are high enough for the recipe and its rise.
FAQ
- Does a larger pan need a different oven temperature?
- This calculation changes ingredient quantities. It does not choose an oven temperature. Follow the recipe, and monitor the bake when you change pan material, shape or size.
- Does it calculate baking time?
- No. Equal batter depth is a useful geometric starting point, but shape, oven behaviour and pan material still affect the bake. Use the recipe's doneness cues rather than multiplying minutes by the pan ratio.
- How do I scale eggs?
- When the multiplier gives a fraction of an egg, a beaten egg can be weighed and divided in the same proportion. Use the egg quantity or mass in your recipe; this tool does not assume that all eggs have one weight.
- Can I compare different measurement units?
- Yes. Set the unit separately for the original pan and the target pan, then enter each pan's actual dimensions. The calculation converts inches to centimetres before comparing the areas.