The short answer: a 12-cup bundt pan holds about 12 cups and a 9x13-inch pan holds about 16.2 cups, a ratio of about 1.3×. Good swap — the volumes are close enough that the bake behaves. That ratio decides everything else on this page — how full the pan gets, how deep the batter sits, and how long the bake takes. Volumes are approximate and assume a standard 2-inch depth; if your pan is deeper or shallower, scale the numbers by the depth.
All amounts in this guide are approximate. Pan volumes vary a little by brand and by how the pan is measured, so treat the cup figures as a planning guide and check the bake by look and feel, not by the clock alone.
The volumes, in a table
| Pan | Volume | In cubic inches | Filled two-thirds full |
|---|---|---|---|
| 12-cup bundt pan | about 12 cups | about 173 cu in | about 8 cups |
| 9x13-inch pan | about 16.2 cups | about 234 cu in | about 10.8 cups |
The ratio is 1.30×, which is where the rest of this guide comes from. Cubic inches are just the cup figures multiplied by 14.44, the number of cubic inches in one US cup — the same conversion the pan size converter uses. A recipe that makes 12 cups of batter, exactly filling the 12-cup bundt pan, fills the 9x13-inch pan to about 74% of its volume. That is over the two-thirds rule, so do not pour the whole batch in: hold back a cup or two of batter and bake it separately, or scale the recipe down.
How full the pan gets
A bundt pan is a ring, so its volume comes from the mould rather than a simple length-by-width calculation. The headline numbers are the ones to trust: the 12-cup bundt pan holds about 12 cups and the 9x13-inch pan holds about 16.2 cups. A recipe that makes 12 cups of batter fills the 9x13-inch pan to about 74% of its volume. That is right at the edge of the two-thirds rule, so fill carefully and leave the last spoonfuls out rather than topping the pan up. Never fill a bundt pan more than two-thirds full — about 10.8 cups in the 9x13-inch pan — because the batter climbs the centre tube as it rises and spills over the top if there is no headroom.
Baking time: how long in the new pan
Baking time does not scale with volume — it scales roughly with the square root of the volume ratio, because heat has to travel through the batter's depth, and depth grows more slowly than volume. That is the rule the pan size converter and the baking time adjuster both use. Multiply the recipe's time by the square root of 1.30, which is about 1.14, and start checking 5–10 minutes before the adjusted time.
| Original time | Adjusted time in the 9x13-inch pan |
|---|---|
| 25 minutes | about 29 minutes |
| 30 minutes | about 34 minutes |
| 35 minutes | about 40 minutes |
| 40 minutes | about 46 minutes |
| 45 minutes | about 51 minutes |
| 50 minutes | about 57 minutes |
| 60 minutes | about 68 minutes |
A sheet cake that baked for 35 minutes in the 12-cup bundt pan needs about 40 minutes in the 9x13-inch pan. That is a guide, not a guarantee: ovens run hot and cold, dark pans bake faster than light ones, and a batter with fruit or chocolate holds moisture longer. Start checking at 30 minutes — a skewer in the centre should come out clean or with a few moist crumbs, and the top should spring back when pressed lightly. If the edges are browning too fast, tent the pan loosely with foil and keep baking until the centre sets.
Worked examples
A sheet cake for the weekend
A sheet cake recipe written for the 12-cup bundt pan makes about 12 cups of batter and bakes for 35 minutes. Poured into the 9x13-inch pan, that batter fills the pan to about 74% of its volume, which is over the two-thirds line — hold back about 1.2 cups of batter and bake it as a small side cake. Set the timer for 40 minutes and check at 35 minutes. The bake will look done at the edges before the middle is set, so trust the skewer, not the colour. Cool in the pan for 10 minutes, then turn out onto a rack: a thinner bake releases more easily but dries out faster, so do not leave it sitting in the pan.
Doubling the batch for a crowd
A double batch makes about 24 cups of batter. In the 9x13-inch pan that is 148% of the pan's volume — more than the pan can hold, so split it across two pans or bake in two rounds rather than risking an overflow. If you split it, both pans bake at the same time as a single batch, roughly 35 minutes, because each pan holds the same depth of batter as the original. If you pour it all into one pan, the depth doubles and the time grows by roughly the square root of the new ratio — but the edges will be dry long before the centre sets, so splitting is the better bake every time. Use the recipe scaler to work out the doubled ingredient amounts, and remember that leavening does not double with everything else.
When the swap goes wrong
The most common failure in this swap is a thin, dry bake. A batter spread thin across a big pan loses moisture fast: the edges crisp, the top dries, and the crumb turns sandy. The fix is a shorter bake and an earlier check — pull the pan when the skewer still shows a few moist crumbs, and serve the bake the same day. Either way, the answer is never to trust the recipe's original time blindly. The time table above is your starting point, and the skewer test is the final word.
How to measure your own pan
The cup figures on this page assume a standard 2-inch depth and a true-to-size pan, and real pans drift from that. The reliable check takes two minutes: put the empty pan on a scale, tare it, and pour in water a cup at a time until the water reaches the rim, counting as you go. The total is the pan's brim-full volume; two-thirds of that is the most batter it should ever hold. If your pan holds noticeably more or less than 16.2 cups, use your measured figure instead of the one on this page — the ratio changes with it, and so does the time. Measuring once and writing the number on a label under the pan saves this whole calculation next time. For more on converting batter and ingredient amounts, see the cups to grams converter.
Practical guidance
Grease and line the 9x13-inch pan the way you would the 12-cup bundt pan, but pay attention to the corners and edges: a rectangular pan has four corners where batter catches and sticks, so butter the corners well and line the base with parchment. If the recipe calls for a water bath — common for cheesecakes in a springform — the swap needs more care: the new pan changes how the water bath fits, so check the pan sits level and the water comes no higher than halfway up the sides. Oven position matters too: a deeper batter belongs on a lower rack so the top does not brown before the centre sets, and a thinner batter belongs in the middle. Rotate the pan once, halfway through, if your oven has a hot spot — most do.
Frequently asked questions
Can I use a 9x13-inch pan instead of a 12-cup bundt pan?
Yes, with the adjustments on this page. The 9x13-inch pan holds about 16.2 cups against the 12-cup bundt pan's 12 cups, a ratio of about 1.3×. The batter will be thinner, so bake it for less time and check early. Do not pour in more batter than two-thirds of the pan — about 10.8 cups — or it will overflow.
How much batter does a 9x13-inch pan hold?
About 16.2 cups brim-full, or about 234 cubic inches, assuming the standard 2-inch depth. For baking, the useful number is the two-thirds fill: about 10.8 cups. That is the most batter the pan should hold. The figure is approximate — measure your own pan with water if you want the exact number, because brands vary.
How do I adjust the baking time?
Multiply the recipe's time by the square root of the volume ratio, about 1.14 here. A 35-minute bake becomes about 40 minutes. Then start checking 5–10 minutes before that adjusted time, because ovens vary. The baking time adjuster does the same calculation for any time you enter.
Will the cake taste different in a different pan?
The flavour stays the same, but the texture changes with depth. A thinner layer bakes faster and dries out more easily, so the crumb is a little firmer and the edges more crisp. Neither is a failure — it is a different bake from the same batter — but if the texture matters, match the depth as closely as you can, or split the batter across two pans.
What if I do not have either pan?
Look for any pan with a similar volume, not a similar shape. The target is about 16.2 cups at two-thirds fill, so any pan holding roughly 16.2 cups brim-full works with the same time adjustment. The pan size converter compares any two pans by volume, and the pan-size hub lists every pan swap on this site.
Do I need to change the oven temperature?
No — keep the temperature the recipe gives and change the time instead. Lowering the temperature for a deeper batter is sometimes suggested, but it changes the rise and the crust, and it is harder to predict than a time change. The one exception is a very deep batter in a small pan, where dropping the oven by 25°F (about 15°C) and adding time helps the centre catch up without burning the top.