Cooking & Kitchen

Baking Time Adjustment Calculator

Bigger bakes take longer, but heat reaches the centre more slowly than the quantity grows, so time rises more gently than the amount does.

The result is the adjusted baking time in minutes for the larger quantity, so it is the time to aim for rather than the original time multiplied by the quantity.

Formula

Adjusted time = original time x square root of the quantity multiplier.

How it works

Doubling a cake does not double its baking time. Heat travels inward from the surface, so the time grows roughly with the square root of the quantity change.

Treat the result as a starting point: ovens differ, so test with a skewer or thermometer near the end of the estimated time.

Worked example

For example, with an original baking time of 30 minutes and a quantity multiplier of 2, the adjusted time is 30 multiplied by the square root of 2, which equals about 42 minutes.

FAQs

Why not just multiply the time by the same factor?
Because only the outer layers heat directly. The centre warms by conduction, which is slower, so time grows more gently than quantity.

Does pan shape matter?
Yes. A wide shallow pan bakes faster than a deep narrow one with the same batter, since more surface is exposed to heat.

Should I change the oven temperature too?
Usually keep the temperature the same and adjust time only. Lowering it slightly can help very large cakes bake through evenly.

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