Why does tin size affect baking time?

When you use a different tin size with the same amount of batter, the depth changes. A larger tin gives shallower batter that bakes faster. A smaller tin gives deeper batter that needs longer, often at a slightly lower temperature, to cook through without burning the outside.

Should I change the oven temperature too?

For significantly deeper batters (much smaller tin), reduce the temperature by 10-20°C to give the centre time to cook without over-browning the crust. For shallower batters, the standard temperature is fine or can be increased slightly.

How accurate is this calculation?

This gives a good estimate, but always check your cake 5-10 minutes before the calculated time. Insert a skewer into the centre — if it comes out clean, the cake is done. Ovens vary significantly, so visual and skewer checks are essential.

Does this work for any type of cake?

Yes, the principle applies to sponges, fruit cakes, and brownies. However, very dense cakes like fruit cakes are more sensitive to depth changes and may need proportionally more extra time when made deeper.

Should I adjust the temperature as well as the time?

For small changes in tin size (within 5cm), adjusting time alone is usually sufficient. For significantly larger or deeper tins, reduce the temperature by 10-15 degrees C and increase the time to prevent the outside from overcooking before the centre is done. For smaller tins, you can keep the same temperature and reduce the time.

BakeCalcs

Baking Time Adjustment Calculator

Adjust baking time when changing cake tin size or scaling a recipe up or down.

Original Recipe

Original Tin Shape

Original Tin Size

Original Baking Time

New Tin

New Tin Shape

New Tin Size

How We Calculate This

Baking time is influenced by the depth of the batter. When you change tin size, the batter depth changes even if the recipe quantity stays the same. This calculator estimates the new baking time based on the area ratio between the original and new tin.

The Approach

Calculate the area ratio: new tin area ÷ original tin area
A ratio above 1 means shallower batter (less time needed)
A ratio below 1 means deeper batter (more time needed)
Time adjustment follows a power relationship with the inverse of the area ratio

Temperature Notes

For significantly deeper batter: reduce temperature by 10°C
For shallower batter: standard temperature or +5-10°C

Frequently Asked Questions

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Last updated: February 2026

All calculations are based on standard ratios and conversions. Results may vary with specific ingredients, equipment, and conditions.