Pan Size Converter
Rescale any baking recipe when you switch to a different tin — round, square, rectangular or loaf — using real pan areas.
Common pan area ratios
Compare baking tins quickly. Sizes are the inside measurements you usually see on packaging.
| Pan | Area (cm²) | Scaling from 23 cm round |
|---|---|---|
| 15 cm (6 in) round | 177 | × 0.43 |
| 18 cm (7 in) round | 254 | × 0.61 |
| 20 cm (8 in) round | 314 | × 0.75 |
| 23 cm (9 in) round | 415 | × 1.00 |
| 25 cm (10 in) round | 491 | × 1.18 |
| 20 cm (8 in) square | 400 | × 0.96 |
| 22 cm (9 in) square | 484 | × 1.17 |
| 33 × 23 cm (9×13 in) rect | 759 | × 1.83 |
| 23 × 13 cm loaf | 299 | × 0.72 |
| 28 × 18 cm sheet | 504 | × 1.21 |
How to use the multiplier
Take every ingredient weight in your recipe and multiply it by the ratio shown. Then watch the batter level: if the new pan has much more surface area, the cake will be thinner and bake faster — start checking 5–10 minutes early and lower the temperature by 10–15 °C for very large pans.
For a deeper batter in a smaller pan, keep the same temperature but expect longer bake times. The formula assumes similar pan depth; very deep or very shallow pans change the math.
Frequently asked questions
A 9-inch pan is not 12.5% bigger than an 8-inch pan — area scales with the square of the diameter, so it is actually about 27% bigger. Batters fill the whole surface, so area (and depth) decide how much batter you need.
Yes — choose Round for the original and Loaf for the new pan. Remember loaf pans are usually deeper, so the batter may need more time to bake through. Check with a skewer rather than relying on the clock.