The bigger pizza is not necessarily a better buy. A 12-inch pie contains about 113 square inches of pizza; a 15-inch pie has about 177 square inches. That makes the larger pizza a little cheaper per bite. (About 8.5 cents versus 8.8 cents per square inch.) But is that a better deal overall? Nope—if the woman orders the bigger pizza, she’ll spend more and possibly consume more calories than she intended.