Convert Baking Pan Sizes & Scale Recipes Instantly
Every baker knows the moment: the recipe says 9" round, but the only clean pan in the cupboard is a square 8". This pan size converter fixes that with one honest number: the area of the pan, and the ratio between the pan you have and the pan the recipe wants.
The Calculator
Four steps to perfect scaling: pick source pan, pick target pan, read results, adjust and bake.
Your Results
Ingredient Multiplier
Scaled Ingredient Amounts
Enter any amount to see the scaled result
Bake Time & Temperature Guidance
Note: These are general guidelines based on batter depth changes. Always check for doneness early.
- Start checking at or slightly before original recipe time
- Visual cues (color, toothpick test, spring-back) matter more than the clock
- Oven temperatures vary - use an oven thermometer if accuracy matters
How It Works
Pick Your Source Pan
Choose the pan the recipe was written for (e.g., 9" round, 8" square, 9x13). Select from standard sizes or type custom dimensions.
Pick Your Target Pan
Choose the pan you actually want to bake in. Type dimensions manually, or (optionally) use camera measurement with a credit card or coin for calibration.
Read Your Results
The tool shows the area of each pan, the ratio between them, and the multiplier to apply to every ingredient in your recipe.
Adjust and Bake
Use the scaled amounts, and follow the bake time/temp guidance. Start checking early - every oven is different.
Why Pan Size Matters
A cake recipe is written for a pan of a certain area. Move that same amount of batter into a bigger pan and the batter spreads thinner, so it bakes faster and the layers come out shorter. Move it into a smaller pan and the batter sits deeper, so the center takes longer to bake and you risk a burnt top with a gooey middle.
Scaling fixes it. You work out the area of both pans, divide the new pan's area by the recipe pan's area, and that ratio is your multiplier. Multiply every ingredient by it, keep the batter depth roughly the same, and the bake behaves like the original.
Quick Reference
Common Pan Swaps
| Pan Swap | Ratio | Multiplier |
|---|---|---|
| 8" round → 9" round | 1.28 | 1 1/4 |
| 9" round → 8" round | 0.78 | 3/4 |
| 8" square → 9x13 | 1.83 | 1 3/4 |
| 9x13 → 8" square | 0.55 | 1/2 |
| 9" square → 8" square | 0.79 | 3/4 |
| 8" square → 9" round | 1.0 | swap as-is |
Conversion Guidance
Standard Pan Areas
Round Pans
| Pan | Area (sq in) |
|---|---|
| 6" round | 28 |
| 8" round | 50 |
| 9" round | 64 |
| 10" round | 79 |
| 12" round | 113 |
Square Pans
| Pan | Area (sq in) |
|---|---|
| 8" square (8x8) | 64 |
| 9" square (9x9) | 81 |
Rectangle Pans
| Pan | Area (sq in) |
|---|---|
| 11x7 | 77 |
| 9x13 | 117 |
| 10x10 | 100 |
| 10x15 jelly roll | 150 |
Decimal to Fraction Conversion
| Decimal | Fraction |
|---|---|
| 0.0625 | 1/16 |
| 0.125 | 1/8 |
| 0.25 | 1/4 |
| 0.33 | 1/3 |
| 0.375 | 3/8 |
| 0.5 | 1/2 |
| 0.625 | 5/8 |
| 0.67 | 2/3 |
| 0.75 | 3/4 |
| 0.875 | 7/8 |
Frequently Asked Questions
Can I swap an 8" square pan for a 9" round pan?
Yes! An 8" square pan (64 sq in) and a 9" round pan (64 sq in) have the same area and can be swapped in most cake and bar recipes without adjusting the ingredients.
How does the camera measurement work?
The camera feature uses your device's camera to capture an image. By holding a standard credit card or coin (known dimensions) in the frame, the browser can estimate your pan's size relative to the reference object. Click on the two ends of the credit card to calibrate, then click on the two edges of the pan to measure. It's entirely optional - manual entry always works and produces identical results.
Do I need to adjust the temperature?
Only slightly. For deeper batter in a smaller pan, lower the temperature by about 25°F and increase baking time. For shallower batter in a larger pan, bake hotter and faster. Temperature changes beyond small increments are risky - prefer changing time over temperature, and always rely on visual cues more than the clock.
Why does pan size matter?
Changing the pan changes the depth of the batter. Deeper batter takes longer to bake through; shallower batter bakes faster and can dry out. Scaling ingredients by the area ratio keeps the batter depth roughly the same, so your bake behaves like the original recipe intended.