Pan Substitution Guide

Area is What Matters

When substituting pan sizes, match the base area as closely as possible. A 20cm round tin = 314 cm². A 18cm square tin = 324 cm² — very close, and a good substitute. An 8-inch (20cm) round = 314 cm² vs a 9-inch (23cm) = 415 cm² — these are not equivalent.

Batter Depth Affects Baking Time

More batter in a smaller pan = deeper cake = longer baking time. Less batter in a larger pan = shallower cake = shorter time. As a rule, reduce temperature by 10°C and check for doneness earlier when going up in pan size.

Tin Volume Guide (UK common)

20cm round: 314 cm² base. 23cm round: 415 cm². 18cm square: 324 cm². 20cm square: 400 cm². 900g loaf tin: approximately 900ml volume. For loaf tins, calculate volume (L×W×H) rather than base area.

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