🍰 Baking Pan Size Converter
Compare the pan your recipe calls for with the pan you have, and get the batter ratio — so you can swap a round tin for a square one, or resize, with confidence.
Original pan (what the recipe calls for)
Your pan
Original area
63.6 in²
Your area
64 in²
Batter ratio
×1.01
Your pan holds 1% more. Multiply the recipe by ×1.01 to keep the same batter depth.
Compares pan floor area (round = π × (d/2)²). Keep the batter depth the same for similar baking; a much bigger or smaller pan will also change the bake time and temperature. 🔒 In your browser.
How the baking pan size converter works
The key is the pan’s floor area, since that sets how deep a given amount of batter sits. The tool computes each pan’s area (a round pan is π × (diameter/2)²; a square or rectangular pan is length × width) and divides the two to give a ratio — how much to scale the recipe to keep the same batter depth.
Matching area keeps the depth, and roughly the bake time, similar. A much larger or smaller pan will still change how fast the centre cooks, so watch it and test for doneness. As a rule of thumb, an 8-inch square pan holds about the same as a 9-inch round.
Frequently asked questions
Can I use a square pan instead of a round one?
Yes, if the areas are close. An 8-inch (20 cm) square pan has about the same area as a 9-inch (23 cm) round pan, so they’re common substitutes. The tool shows the exact ratio so you can adjust the batter if they differ.
How do I convert between pan sizes?
Compare their floor areas. Divide the area of your pan by the area the recipe calls for — that ratio is how much to scale the recipe to keep the same batter depth. The tool does the area maths for both shapes.
What if my pan is bigger than the recipe’s?
The batter will sit shallower and bake faster, so lower the temperature slightly or check for doneness earlier. Scale the recipe up by the area ratio if you want to keep the original depth.
How do I find a round pan’s area?
Area = π × (diameter ÷ 2)². A 9-inch round pan is π × 4.5² ≈ 63.6 square inches. The tool calculates this automatically when you pick the round shape.
Does pan depth matter too?
Yes — this tool compares floor area (which sets batter depth for a given volume). If your pan is much shallower or deeper than usual, factor that in and adjust the bake time and fill level accordingly.