How many boxes of cake mix for a 15x11 cake pan?

For a 15x11-inch cake pan, you typically need about 2 to 3 boxes of cake mix, depending on the brand and recipe instructions. Most standard cake mix boxes yield about 4 to 5 cups of batter, and a pan of that size usually requires around 10 to 12 cups of batter. It's always best to check the specific box instructions for the best results.