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Calculator Tools
Baking Calculators

Baking Pan Size Converter

Swap one baking pan for another and scale the batter and baking time to match.

Enter values

Results update as you type.

Result

Scale the recipe by

1.6839 ×

Start checking 10 minutes before the estimated time — pan material and colour change baking speed as much as size does.

Original pan area
314.2 cm²
New pan area
529 cm²
Estimated baking time
42 min
Batter depth change
Shallower — bakes faster
Capacity change
68.4%
Eggs in a 3-egg recipe become
5.05

About the Baking Pan Size Converter

Pans hold batter by area, not diameter, so a 9-inch round holds about 27% more than an 8-inch one. Work out the area of both pans, take the ratio, and you know exactly how much to scale the recipe — and roughly how the baking time will shift.

Also known as: pan size conversion, cake tin converter, change pan size recipe, round to square pan.

How to use this calculator

  1. Enter original pan, new pan, original baking time and the other fields.
  2. The result updates instantly as you type — press Calculate (or Enter) at any time.
  3. Review the breakdown shown under the main result.
  4. Use Copy result or Share to save the answer or send a link with your inputs.

Formula

scale factor = new pan area ÷ old pan area

Worked example

Using the values pre-filled in the calculator above:

  • Original pan: Round
  • Original diameter = 20 cm
  • New pan: Square or rectangular
  • New length = 23 cm
  • New width = 23 cm
  • Original baking time = 35 min

the calculator returns:

  • Scale the recipe by: 1.6839 ×
  • Original pan area: 314.2 cm²
  • New pan area: 529 cm²
  • Estimated baking time: 42 min

Frequently asked questions

Can I use a square tin instead of round?

Yes — a square tin holds about 25% more than a round one of the same measurement, so an 8-inch square roughly replaces a 9-inch round.