Here’s a trick question going the rounds (pun intended) recently*: For the same price, which of these two options provides the best pizza value—one 9 incher or two 5-inch pies?

Many consumers would go for the two smaller pizzas. But going strictly by area, they then come up 38% short of the single large pie. Two for one is not a good deal in this case.

For comparing pizzas by size and price, even those of us that know the math can benefit from calculators like these:

• Nathan Yau’s Pizza Exchange Rate posted earlier this week—nicely slider-barred with a graphic view to make sure you get a fair deal. For example, if you order a mega 30 inch pizza that cannot be delivered, do not settle for anything less than 36 five-inch ones.
• Better yet is this value-based computer by DQYDJ (Don’t Quit Your Day Job) blogger “PK”.

For a fascinating study demonstrating the significance of how poorly people relate diameter of pizzas to their value, see this 2001 Marketing Science publication on Pizzas: p or Square? Psychophysical Biases in Area Comparisons. The research suggests that “consumers understand the [pizza] size increase more readily when presented with pictures of the various sizes versus when merely presented with the diameters.”

The authors go on to say that “the best strategy, however, is to give the actual area numerically.” Though this is obvious, it seems to me that most people who buy pizza would be overwhelmed by all this mathematical detail.

Am I being overly pessimistic?

*Twitter post about restaurant’s mathematical pizza miscalculation goes mega-viral, Michelle De Pacina, July 4, 2022 post by Yahoo.