Pan Size Converter

Calculate the area of your round pan (π × radius²) and the area of the rectangular pan (length × width), then scale every ingredient by the ratio of the new area to the old one.

Batter depth changes even when the recipe amount doesn't. A larger pan spreads the same batter thinner, so it bakes faster; a smaller, deeper pan needs more time for the center to cook through.

Area is the most useful measure for typical cake/bar pans of similar depth, since batter is poured to a similar fill level. For very differently shaped pans (like a bundt vs. a sheet pan), also compare volume capacity and use your judgment on fill depth.