How much does pizza price vary across the US? In order to answer that question, Eater looked at the margherita pie at every single VPN-certified restaurant in the country (more on what VPN means below). That's 73 VPN-certified pizzerias total in the US, some of which are separate locations of chains. The result is the infographic above.
As you can see, the cheapest VPN margheritas available in the US are from Kentucky, where the mini-chain Smashing Tomato serves them for $8.90. Tied for most expensive are some of the most expensive areas in the country: the Bay Area, New York City, and Connecticut all serve $16 pies on average. (Il Pizzaiolo in Pittsburgh also serves a $16 margherita, but let's consider them an outlier as those guys are hardcore and fly in their cheese from Naples every week.) The average price of VPN margherita pizza in the US is $13.21. Which sounds about right.
Below, more on what VPN pizza is, exactly, and why Eater chose it as a standard for the price index.
Why the VPN margheritas? To get a good look at the geographic differences in pizza prices, you need to have as close to a standardized pizza as possible. The VPN is a standardized certification: it stands for Verace Pizza Napoletana, a stamp of approval given out by the Delegation of the Associazione Vera Pizza Napoletana, an organization that approves what they consider to be proper, wood-fired pizza Napoletana.
VPN pizzas must adhere to the following rules [PDF]:
1. They must be cooked in a wood-fired oven at about 900 degrees.
2. The dough must be made with wheat flour type "00," which designates a very refined flour.
3. They can only use one of these three types of fresh tomatoes: S.Marzano dell'Agro Sarnese-nocerino D.O.P., Pomodorini di Corbara (Corbarino), or Pomodorino del piennolo del Vesuvio D.O.P..
4. They can only use one type of canned tomato, Pomodoro pelato S.Marzano dell'Agro Sarnese-Nocerino D.O.P. Also, according to the official rules, "If peeled tomatoes are used they should be strained, broken up and homogenised by hand." (Some allowances are made for using plain old Roma tomatoes.)
5. Cheese must be mozzarella di bufala campana D.O.P, mozzarella S.T.G., or a certified Fior di Latte.
6. Olive oil must be extra virgin, basil must be fresh, salt must be from the sea.
7. There are additional requirements for technique that address making the dough, shaping the pizza, cooking time, and more.
As you can see, those are pretty strict rules that result in a somewhat standardized pizza situation. And, while some might argue the VPN certification in no way implies that a pizza is actually good, it still provides a decent basis for the purpose of a price index.