Baking Pan Size Converter
Scale a recipe from one baking pan or tin to another, round, square or rectangular, in centimetres or inches: the factor to multiply the ingredients by and how deep the batter will be.
Result…
How it's calculated
Area: round = π × (diameter ÷ 2)² · square = side² · rectangle = length × width Scaling factor = your pan area ÷ recipe pan area Depth with the recipe unchanged = recipe depth ÷ scaling factor 1 in = 2.54 cm, so 1 in² = 6.4516 cm²
Batter or dough fills a pan to a depth, so the amount you need grows with the pan's floor area, not its diameter: a round pan 2 times as wide holds 4 times as much. The calculator finds each pan's area from its inside top measurements, divides yours by the recipe's to get the factor to multiply every ingredient by, and shows how deep the batter would sit if you kept the recipe as it is. Sloped sides, rounded corners and pan depth are ignored, so for very different pans compare by filling each with water. Inches and centimetres use the exact factor 1 in = 2.54 cm.
Your numbers, step by step
About the Baking Pan Size Converter calculator
This baking pan size converter tells you how much to scale a recipe when your cake tin or baking dish is a different size or shape from the one in the recipe. Choose centimetres or inches, then enter the recipe pan and your own pan as round (diameter), square (side) or rectangle (length and width). The calculator compares their floor areas and gives the factor to multiply every ingredient by so the batter stays the same depth. If you would rather keep the recipe as it is, enter the batter depth and it shows how deep the batter will sit in your pan. It suits home bakers, anyone swapping a round tin for a square one, and cooks halving or doubling a tray bake. Each step is shown with your measurements.
How to use it
- Choose “Centimetres” or “Inches” under “Units”.
- Pick the “Recipe pan shape” and enter its “Recipe pan diameter or length” (and width for a rectangle), measured across the inside top edge.
- Pick “Your pan shape” and enter its size the same way.
- Optionally enter the “Batter depth in the recipe pan (optional)”.
- Multiply every ingredient by the result, and check the bake a little early.
Worked example
A recipe for a 13 × 9 in rectangular pan covers 117 in². A 9 in round pan covers π × (9 ÷ 2)² = 63.62 in² (410.43 cm²). The factor is 63.62 ÷ 117 = 0.544, so use a little over half of each ingredient. If you poured the full recipe, which sits 1.5 in deep in the large pan, into the round one, it would be 1.5 ÷ 0.544 = 2.76 in deep.
Updated
Questions people ask
How do I convert a recipe for a different pan size?
Work out the area of both pans, divide your pan's area by the recipe pan's area, and multiply every ingredient by that factor. The batter then sits at the same depth, so it bakes in a similar way.
What is the formula for the area of a round cake tin?
Area = π × (diameter ÷ 2)². A 20 cm round tin is about 314 cm², while a 20 cm square tin is 400 cm², so the square tin needs about 27% more batter.
Why can't I just compare the pan diameters?
Area grows with the square of the diameter, so a pan twice as wide holds four times as much. Scaling by the diameter alone is the most common mistake and leaves the cake far too thin or too deep.
Do I need to change the baking time for a different pan?
Often, yes. Deeper batter needs longer and shallower batter less, and dark metal or glass pans bake faster than light ones. Start checking earlier than the recipe says. To scale amounts by a number of servings instead, use the recipe scaler.
What does the pan size converter not account for?
It uses the floor area only, so sloped sides, rounded corners and a much taller or shallower pan change the result a little. For an unusual pan, fill both with water and compare the volumes.