Baking Pan Size Converter — area & scaling
Compare baking pan sizes by area and get a scaling factor when swapping pans — in your browser.
🔒 Runs entirely in your browser. Your input and output are never sent to a server or stored — fully private.
Areas assume the same batter depth. If the depth changes, use the volume ratio. Watch the bake — a shallower pan cooks faster, a deeper one slower.
About this tool
This baking pan converter compares pans by area so you can swap the size or shape a recipe calls for with confidence. Choose round, square or rectangular pans, enter their dimensions, and it works out each pan's area and the scaling factor between them — telling you how much to increase or reduce the batter. It helps when you only own one tin, or want to turn a layer cake into a sheet cake. Everything is calculated in your browser, so your measurements stay on your device and the tool keeps working offline.
Frequently asked questions
Why compare pans by area, not diameter?
Because area, not width, determines how much batter a pan holds and how thick the bake turns out. Area grows with the square of the size, so a small change in diameter is a big change in capacity. A 9-inch round pan has about 27 percent more area than an 8-inch one, even though it is only an inch wider. Matching the area is what keeps your layers the right depth and the baking time roughly the same.
How do I use the scaling factor?
Multiply each ingredient by the factor the tool gives you. If you move to a pan with 1.5 times the area, make 1.5 times the batter. Try to keep the batter depth similar to the original so the timing stays close, though a deeper or shallower fill will change the bake. Check for doneness a little earlier or later than the recipe says, and lower the temperature slightly for a much larger, deeper pan.
Does it run on my device?
Yes. The areas and the scaling factor are calculated by JavaScript in your browser, so the pan sizes you enter are never uploaded to a server. Once the page has loaded the converter works fully offline, with no account needed, and nothing you type ever leaves your own device.