Baking tin comparisons

A recipe is written for a tin's area, not its name. Move the same mixture into a wider tin and it sits shallower, bakes faster and browns more — which is why "I only have a 23 cm tin and the recipe says 20" has a number for an answer rather than a shrug.

Each page gives that number both ways, along with how deep the batter ends up if you pour it straight across. Pairs more than double each other in area are left out: that is not a substitution.

Why depth sets the baking time and diameter barely does

Heat reaches the middle of a cake from the outside in, so what decides when it is done is how far it has to travel — the depth of the batter, not the width of the tin. Two tins of very different diameters at the same depth bake in close to the same time; the same mixture spread thinner is done sooner and browns more at the edges while it waits.

That is why the useful number when swapping tins is the area ratio rather than the diameter ratio, and why the answer is to change the time rather than the temperature. A lower oven does not fix a cake that is too shallow; it only takes longer to reach the same place.

All 48 comparisons

All baking tin sizes