One 18″ Pizza Is More Pizza Than Two 12″ Pizzas, Math Shows Us Why – Primer Tackling the Serious Issues

Two mediums for a good lookin’ price? It’s a trap: Why you should ALWAYS order the large pizza.

one 18 inch pizza is more pizza than two 12 inch pizzas - math shows us why

Pause for a moment and consider a question that really matters: what size pizza should you order?

If you’ve found your way to Primer, it’s likely you're the kind of saavy consumer who likes a good deal, and hates getting taken for a ride. So here’s the thing:

All those two-medium-pizza deals you always see and probably buy, thinking “two for one? That’s got to be a better deal!” Scam city.

Archimedes, mathematicians, and 7th grade geometry teachers have known the truth about pizza sizes for years, but it’s time to spread the message to the masses:

A large pizza is almost always a better deal than two mediums. Because it’s simply more pizza. Why? Math.

It has to do with the mathematical nature of the area of circles. When you increase the width of your pizza it actually adds to the total size of your pie exponentially. For example, a 16-inch large might seem twice as big as an 8 inch small but it’s actually four times as much pizza.

Skeptical about the math? Let's compare a single large 18” pizza to that 2 medium 12” deal we mentioned earlier:

As you recall, the formula for the area of the circle is πr², with r being the radius of the pizza (i.e., half the diameter, which is its size).

Area of two 12” pizzas:

12/2 = 6   6×6=36   36xπ = 113.1 in² x 2 = 226.2 in²

Area of one 18” pizza:

18/2=9   9×9=81   81xπ = 254.5 in²

The numbers don’t lie.

But what about crust, you might ask? Crust ratio is generally the same across pizza sizes, so the 12″ pizzas have less non-crust pizza than the 18″.

A study of nearly 4,000 pizzerias confirms it: if you buy based on price-per-square-inch, the large is always a better deal.

Stillman Brown is a writer and TV producer who has created prime time content for National Geographic, Discovery, Travel Channel and many others. His interests span science & the natural world, personal growth, and food. He lives in Tulsa, Oklahoma.

  • Michael Scott

    So we need to use Pi when ordering a pizza pie. I was told they’d be no math.

  • Big O

    The best line of your article:

    “Why? Math.”


  • Bruce

    Love the premise of the article, but if you want to get technical, you REALLY have to go there.

    Math checks out, but does this really prove that you get more pizza? No, because you don’t calculate volume. This is where NPR went wrong. Calculating area would be a great indicator if the pizza were completely flat. But most pizza chains have crusts that rise higher than the middle of the pizza. So toppings aside, the circumference of two mediums is greater than one large, so I’m not sure if you’re really getting more pizza.

    Still a great article and in the end I’ve definitely been enlightened! Thanks

    • TMann

      Ah, but now you let off density (or mass?) as a variable as well. Correct me if I’m wrong, but a pizza crust is made entirely flat from edge to edge; the puffy “crust” at the edges contains the same volume of pizza dough per square inch as the “flat” crust in the middle. The extra volume that you’re seeing consists merely of air bubble contained inside of the baked dough. So for all intents and purposes, we can accurately assume a uniform volume of pizza across the width of the pie.

      See kids? Math CAN be fun if you apply it in the right setting…

      • Bruce

        The only problem is that each pizza is different. Some prepare it flat, some do not. So for all intents and purposes, you can’t assume a uniform volume…

        • James LaFevers

          Couldn’t we just.. take two medium pizzas weigh them then weigh a large and which one weighs more is more pizza?

    • Pessimissity

      So toppings aside, the circumference of two mediums is greater than one large, so I’m not sure if you’re really getting more pizza.??? That’s not how math works. Go back to school!

  • I heart ubuntu

    What about extra large?

  • Diana Carter

    Cool revelation, except where in the world can you get an 18 in pizza?? According to popular pizza chains that I looked at (Dominos, Pizza Hut, Papa Murphy’s, Papa John’s), the large is listed as 14 in. Extra large in those places are listed as only 16 in.

  • Aleks Spirkoski

    But what if you get Cheezy crust? That throws the whole math off..

  • Stephanie Raymond

    Pi r squared….

    No, pi r round. 😛