Why it is best to always buy the largest pizza

Yesterday I bought a pizza. Because I had to carry it home on my bicycle, I decided to get a medium instead of a large. I immediately regretted the decision. Here is why.

I have always known it to be best when buying food to just get the biggest. I mean.... more is better right?! Just how much better is it though?

I went onto Papa John's website here to get some pizza sizes and prices. After that, I figured out the square inches per pizza and the price per square inch. See the stats below:

Pizza Sizes and Prices	Size in Square Inches	Price per square inch
Small (10") = $11	78.5 Square inches	14 cents / Sq In
Medium (12") = $14	113.1 Square inches	12 cents / Sq In
Large (14") = $16	153.9 Square inches	10 cents / Sq In
Extra Large (16") = $19	201.1 Square inches	09 cents / Sq In

So what does this all mean? For one, it means that the large pizza is basically TWICE the size of the small pizza even though it is only $5 more (not $11 more like the price of a small). It means that if the extra large pizza was priced the same as the small, it would cost $28. If the small pizza was priced the same as the extra large, it would cost only $7.40.

So yesterday when I bought the medium pizza, for just $2 more, I could have gotten 40.8 square inches more.

So why all this math? This way I can justify getting the large Slurpee, the large Blizzard, the extra large pizza etc... (actually, the best idea is just to get the largest item and split it with someone else).