Cake Pan Size Conversions: Round, Square, 9×13 and Loaf Pans Compared by Area
Switching pans is mostly a geometry problem. Compare surface area, keep the batter depth similar and adjust the bake time, and most recipes move over cleanly.
To swap cake pans, compare their surface area and keep the batter at a similar depth. A 9-inch round (about 64 square inches) holds almost exactly the same as an 8-inch square (64 sq in). Two 9-inch rounds (127 sq in) roughly fill one 9 x 13-inch pan (117 sq in). Keep the oven temperature the same and adjust the time: shallower batter bakes faster, deeper batter slower.
Pan area chart
| Pan | Area (sq in) | Area (sq cm, approx.) | Roughly equivalent to |
|---|---|---|---|
| 6-inch round | 28 | 182 | Half an 8-inch round |
| 8-inch round | 50 | 324 | 9 x 5 loaf by area (but much shallower) |
| 9-inch round | 64 | 410 | 8-inch square |
| 10-inch round | 79 | 507 | 9-inch square |
| 8-inch square | 64 | 413 | 9-inch round |
| 9-inch square | 81 | 523 | 10-inch round |
| 11 x 7-inch | 77 | 497 | 9-inch square |
| 9 x 13-inch | 117 | 755 | Two 9-inch rounds (slightly thicker) |
| 8 1/2 x 4 1/2-inch loaf | 38 | 247 | About 3/4 of a 9 x 5 loaf |
| 9 x 5-inch loaf | 45 | 290 | 8-inch round by area (but much deeper) |
| 15 x 10-inch jelly roll | 150 | 968 | About 1 1/4 times a 9 x 13 |
| 18 x 13-inch half sheet | 234 | 1,510 | Two 9 x 13 pans |
Round pan area = 3.14 x radius x radius. Rectangular pan area = length x width. Measure across the top inside edge, not the outside rim. Figures are rounded.
How to convert, step by step
- Find the area of the original pan (or pans, if the recipe uses two layers) from the chart or the formulas above.
- Find the area of your pan.
- Divide new by old. A result between about 0.9 and 1.1 means the recipe fits as written. Example: one 9 x 13 (117) divided by two 9-inch rounds (127) is 0.92, so it fits, and the cake will be slightly thicker.
- If the ratio is far off, scale the recipe by that ratio, or choose a different pan. A 1.5 ratio, for example, means making one and a half times the batter.
- Keep the temperature the same and adjust the time, as below.
Depth matters as much as area
Area tells you how far the batter spreads; depth decides how long the center takes to set. Most layer cake pans are 2 inches deep, and recipes assume the pan will be filled about half to two-thirds full. Filling deeper than that risks overflow and a sunken, underbaked center; see why cakes sink in the middle.
- Same depth of batter: the bake time stays close to the original.
- Shallower batter (larger pan): start checking 5–10 minutes early.
- Deeper batter (smaller or taller pan): expect a longer bake. Many bakers lower the temperature by about 25°F for very deep pans so the edges do not dry out before the middle sets, and tent with foil if the top browns early.
Loaf pans are deep for their area, which is why a loaf takes far longer than the same batter baked as muffins or a sheet. A raw, gummy center in a loaf is usually a depth or time problem; see why banana bread is gummy in the middle.
Bundt and tube pans: use volume, not area
Bundt and tube pans have a center tube and sloped or fluted sides, so area does not work well. Instead:
- Fill the pan with water to the brim, measuring cups as you go. A pan described as “10-cup” or “12-cup” refers to this full volume.
- Plan to fill it about two-thirds full with batter.
- If the recipe was written for layer pans, measure the batter volume and check that it is about two-thirds of the Bundt pan’s capacity.
Bundt cakes bake longer than layers of the same batter, often 45–60 minutes or more at 350°F (180°C). Test with a long skewer.
Pan material and color
- Light aluminum or aluminized steel: the baseline most American recipes assume.
- Dark or nonstick metal: absorbs more heat and browns faster. Pan makers commonly suggest lowering the temperature by about 25°F.
- Glass and ceramic: heat up slowly but hold heat; edges can overbake. Lowering the oven by 25°F is common advice for glass.
- Silicone: browns less; set it on a baking sheet for stability.
For a starter set of sizes and materials, see our cake pans guide.
Common swaps at a glance
| Recipe calls for | You can use | Time change |
|---|---|---|
| Two 8-inch rounds | One 9-inch square (slightly thicker) | Add a few minutes |
| Two 9-inch rounds | One 9 x 13 | Add about 5–10 minutes |
| One 9 x 13 | About 24 standard cupcakes (per Wilton’s yield guide) | Much shorter; about 18–22 min |
| One 8-inch square | One 9-inch round | About the same |
| One 9 x 5 loaf | One 9-inch square (shallower) | Much shorter; check early |
Bottom line
Match area to area, keep the batter about the same depth, and change the time rather than the temperature. A 9-inch round equals an 8-inch square, two 9-inch rounds equal a 9 x 13, and a half sheet equals two 9 x 13s. When in doubt, fill to two-thirds and check early.
FAQ
Can I bake a 9 x 13 recipe in two 9-inch round pans?
Yes. The areas are close (117 vs 127 sq in). The layers will be slightly thinner, so start checking for doneness about 5–10 minutes early.
Is an 8-inch square bigger than an 8-inch round?
Yes, by about 27%. An 8-inch square (64 sq in) holds about the same as a 9-inch round.
Should I change the oven temperature for a different pan?
Usually not. Keep it the same and adjust the time. Exceptions are very deep pans, dark pans and glass, where many bakers go about 25°F lower.
How full should a cake pan be?
About half to two-thirds full. That leaves room for rising without overflow.
