A typical box of cake mix makes about 4 to 5½ cups of batter once you add the eggs, water, and oil. The amount depends on the brand, flavor, and box size. Mixes that recommend the same pan size can still make different amounts of batter. [Wilton’s guide](https://blog.wilton.com/wedding-cake-guide/)

Measure your nonstandard pan’s capacity by filling it with water, then dry it before adding batter. For an ordinary cake pan, fill it about halfway to two-thirds full to leave room for the cake to rise. A pan that holds 8 cups of water to the brim would need roughly 4 to 5⅓ cups of batter. [Wilton’s pan guide](https://wilton.com/baking-inspiration/cake-baking-serving-guide/)

To plan more accurately, measure how much batter your usual mix makes once and write down the amount.