How the conversion works
- Area decides the multiplier. A round pan's area is π × (diameter ÷ 2)², a square or rectangular pan's is width × length. Divide your pan's area by the recipe pan's area — that's how much to multiply every ingredient by, if you want the same thickness.
- Depth changes the picture. If you enter the depth of both pans, the calculator compares volume (area × depth) instead.
- Bundt, tube and odd shapes: compare by capacity — fill each pan with water and measure.
- Baking time: deeper batter bakes longer, shallower batter faster. Keep the recipe's temperature, start checking early, and use a toothpick. For much deeper pans some bakers lower the oven by 25°F.
Standard U.S. pan sizes
| Pan | Area (in²) | Capacity to the rim |
|---|---|---|
| 6" round | 28.3 | — |
| 8" round | 50.3 | 6 cups |
| 9" round | 63.6 | 8 cups |
| 10" round | 78.5 | — |
| 8×8" square | 64.0 | 8 cups |
| 9×9" square | 81.0 | 10 cups |
| 11×7" rectangle | 77.0 | 10 cups |
| 9×13" rectangle | 117.0 | 14 cups |
| 9×5" loaf | 45.0 | 8 cups |
| 10×15" jelly roll | 150.0 | — |
| 13×18" half sheet | 234.0 | — |
Capacities are approximate and measured to the rim — not how much batter to use. Most cake batter fills a pan about halfway.
Common pan swaps
| From → to | Multiply recipe by | In practice |
|---|---|---|
| 9×13" rectangle → 8×8" square | ×0.55 | about ½ (slightly thinner) |
| 9×13" rectangle → 2 × 9" round | ×1.09 | use the full recipe |
| 9×13" rectangle → 2 × 8" round | ×0.86 | about ⅞ |
| 8×8" square → 9×13" rectangle | ×1.83 | nearly double |
| 8" round → 9" round | ×1.27 | about 1¼ |
| 8" round → 10" round | ×1.56 | about 1½ |
| 9×9" square → 8×8" square | ×0.79 | about ¾ |
| 9" round → 8×8" square | ×1.01 | same amount |
| 9" round → 2 × 8" round | ×1.58 | about 1½ |
Frequently asked questions
How do I convert a 9x13 recipe to an 8x8 pan?
Multiply the recipe by about 0.55. A 9x13 pan has 117 square inches and an 8x8 has 64, so the smaller pan holds a little more than half. Halving the recipe works if you don't mind a slightly thinner cake.
Can I bake a 9x13 recipe in two 9-inch round pans?
Yes — it's the most common swap. Two 9-inch rounds have about 127 square inches, 1.09 times a 9x13, so the layers come out a little thinner. Use the same batter and start checking for doneness early.
Does the baking time change with a different pan?
Usually. Deeper batter needs longer, and some bakers lower the oven by 25°F for much deeper pans so the edges don't overbake. Shallower batter bakes faster. Start checking well before the recipe's time and use a toothpick.
What do I do with 1.64 eggs?
Round to the nearest whole egg for forgiving batters, or beat an extra egg and add part of it. For exact results, weigh: beat the egg and use the matching fraction by weight.
How do I convert to a bundt or tube pan?
Match by capacity, not by bottom area — fill the pan with water to measure it. Bundt cakes are deep, so they usually need noticeably longer than a 9x13.