Converting a recipe between tin sizes and shapes. Scale by base area rather than diameter, and a round 20 cm tin is not equivalent to a square 20 cm one: the square holds about 27 percent more.
Also called: cake tin conversion, pan size converter.
Multiply every ingredient by 1.27. The original tin has 314.16 cm² of base and the new one 400 cm², a difference of 27.32%. Baking time follows batter depth rather than quantity, so a scaled recipe at the same depth bakes in about the same time.
Batter depth governs baking time, so keeping depth constant means scaling by base area. That is why a round 20 cm tin and a square 20 cm tin are not interchangeable: the square has 400 cm² against the round's 314, about 27 percent more. Scaling by diameter instead of area is the common error and produces a cake either overflowing or too shallow. Baking time changes with depth rather than quantity, so a scaled recipe at the same depth bakes in roughly the same time.
scale by base area, because batter depth is what governs baking timeEach of these is asserted on every build. If a change to the engine ever moved one of these answers, the build would fail before the page could print it.
Multiply the recipe by1.27
400/314.16, the 27 percent difference this page exists to show
Open this exampleMultiply the recipe by1
boundary
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