Update: my boxed cake mix made 40% more batter than the box said and I almost overflowed the pan
So I was making a simple vanilla sheet cake last Saturday for my neighbor's potluck, and I grabbed a box of Duncan Hines that said it made two 8 inch rounds. I mixed it up in my big bowl and kept thinking the batter looked like a lot. I poured it into one 13x9 pan instead of two rounds and it came up almost to the rim. I put it in the oven anyway and it puffed up and dripped all over the bottom, smoke alarm went off and everything. I looked at the back of the box again and it said each 8 inch round should get about 2 cups of batter, but the full batch was closer to 5 and a half cups, which is way more than the label implied. I ended up scooping out about a cup into a muffin tin and those little cupcakes came out perfect while the big cake was a little dense. I guess the box numbers are just a guide, but it felt like a mini win that I saved it at all. Has anyone else weighed their batter before pouring, or am I overthinking this?