18 cm / 7 in square vs 23 cm / 9 in square
| 18 cm / 7 in square | 23 cm / 9 in square | |
|---|---|---|
| Size | 18 × 18 cm | 23 × 23 cm |
| Base area | 324 cm² | 529 cm² |
| Usual depth | 5 cm | 5 cm |
| Holds | 1.62 L | 2.65 L |
Can you swap them?
Scale the mixture, or accept a flatter cake. 23 cm / 9 in square has 63.3% more area, so a 18 cm / 7 in square mixture poured straight in sits 61% as deep. It still bakes, and it browns more at the edges for being shallower. Multiplying by 1.63 restores the depth the recipe was written for.
There is a tin between these two — 20 cm / 8 in square at 400 cm² — so the jump does not have to be taken in one step.
Scaling the recipe
| Recipe written for | Baked in | Multiply by | Or leave it and get |
|---|---|---|---|
| 18 cm / 7 in square | 23 cm / 9 in square | 1.63 | 61% of the depth |
| 23 cm / 9 in square | 18 cm / 7 in square | 0.61 | 163% of the depth |
Multiply every ingredient, including the eggs — round to the nearest half egg and adjust the liquid rather than rounding a whole one up.
Baking time
A mixture 61% as deep is done earlier, not cooler. Leave the temperature alone, start testing at about 61% of the stated time, and let the skewer decide. Why depth sets the time and diameter barely does →
Frequently asked questions
Can I use a 23 cm / 9 in square instead of a 18 cm / 7 in square?
Yes, with the mixture multiplied by 1.63. 23 cm / 9 in square has 529 cm² of base against 324 cm², so an unscaled 18 cm / 7 in square recipe sits 61% as deep and bakes faster.
What is the difference between a 18 cm / 7 in square and a 23 cm / 9 in square?
18 cm / 7 in square has a base area of 324 cm² and 23 cm / 9 in square has 529 cm² — 23 cm / 9 in square is 63.3% larger. At their usual depths they hold 1.62 L and 2.65 L.
Do I need to change the baking time between a 18 cm / 7 in square and a 23 cm / 9 in square?
Yes. Moving a 18 cm / 7 in square mixture into 23 cm / 9 in square makes it 61% as deep, so start checking at about 61% of the stated time. Depth drives baking time far more than tin diameter does.
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18 cm / 7 in square in full · 23 cm / 9 in square in full · All tin comparisons · All baking tin sizes