About comparing pizza value
When two pizzas come in different sizes and prices, the cheaper sticker price is rarely the better deal. The right way to compare is price per square inch of pizza, because that measures how much food you get for each dollar. This calculator takes the price and diameter of two pizzas, works out the area of each, and tells you which one costs less per square inch and by how much.
The reason size matters so much is geometry. A pizza is a circle, and the area of a circle grows with the square of its radius. That means a small bump in diameter is a big jump in actual pizza. Going from a 14-inch to an 18-inch pizza adds only 4 inches of width but roughly 65 percent more food. Because menus rarely raise the price by that much, the larger pizza almost always wins on value, which is exactly the kind of thing this tool makes obvious in a second.
Use it before ordering takeout, when a deal offers two mediums versus one large, or any time you want to stop overpaying for the illusion that a smaller pizza is cheaper.
How the math works
The calculator converts each diameter into area, then divides price by area:
Radius = Diameter / 2 Area = pi x Radius^2 (pi is about 3.14159) Price per sq inch = Price / Area Better deal = the pizza with the lower price per square inch
- Diameter to radius: halve the across-the-middle measurement before squaring it.
- The square is the key: area scales with diameter squared, so doubling the diameter quadruples the pizza.
- Lower is better: the smaller the price per square inch, the more pizza you get per dollar.
Worked example
Pizza A is 14 inches for 15 dollars. Pizza B is 18 inches for 19 dollars. Which is the better deal?
- Pizza A area: pi x 7^2 = about 154 square inches.
- Pizza A value: 15 / 154 = about 0.097 dollars per square inch.
- Pizza B area: pi x 9^2 = about 254 square inches.
- Pizza B value: 19 / 254 = about 0.075 dollars per square inch.
- Compare: 0.075 is lower than 0.097, so Pizza B is roughly 23 percent cheaper per square inch.
Pizza area by diameter
Area for common pizza sizes, showing how quickly food grows with diameter.
| Diameter | Radius | Area (sq in) | Relative size |
|---|---|---|---|
| 10 in (small) | 5 in | 79 | 1.0x |
| 12 in (medium) | 6 in | 113 | 1.4x |
| 14 in (large) | 7 in | 154 | 2.0x |
| 16 in (x-large) | 8 in | 201 | 2.6x |
| 18 in (party) | 9 in | 254 | 3.2x |
Common pitfalls
- Comparing by diameter instead of area. An 18-inch is not "a bit bigger" than a 14-inch; it is about 65 percent more food. Always square the radius.
- Trusting the lower sticker price. A cheaper small pizza usually costs more per square inch, so the cheaper pie can be the worse deal.
- Assuming two mediums beat a large. Two 12-inch pizzas often give less total area than one 18-inch, for more money. Run both through the tool.
- Ignoring crust style. The area method compares top-down size; a deep-dish has more food by volume than a thin-crust of the same diameter.
- Forgetting fees. Delivery charges and minimums are flat, so spreading them over a larger order lowers the real cost per square inch even further.
Frequently asked questions
How do you compare pizza value by size?
Compare the price per square inch, not the price per pizza or per inch of diameter. A pizza is a circle, so its area is pi times the radius squared, where the radius is half the diameter. Divide the price by that area to get the cost per square inch, and the pizza with the lower cost per square inch is the better value. Because area grows with the square of the diameter, a larger pizza almost always gives more food per dollar even when its sticker price looks higher.
Why is a larger pizza usually a better deal?
Because the area of a circle grows with the square of the diameter, not in a straight line. Doubling the diameter quadruples the area. An 18-inch pizza has about 254 square inches versus 154 for a 14-inch, roughly 65 percent more food, yet it rarely costs 65 percent more. That gap is why the per-square-inch price of a large pizza is typically well below that of a small or medium, making the large the value pick in most cases.
How much bigger is an 18-inch pizza than a 14-inch?
An 18-inch pizza has an area of pi times 9 squared, about 254 square inches. A 14-inch pizza has an area of pi times 7 squared, about 154 square inches. So the 18-inch is roughly 1.65 times the food, about 65 percent more, despite being only 4 inches wider in diameter. This is the classic surprise of pizza math: a modest jump in diameter is a large jump in actual pizza.
Are two medium pizzas more than one large?
Often no. Two 12-inch mediums give 2 times about 113, roughly 226 square inches, while a single 18-inch large gives about 254 square inches, more pizza in one pie. You usually pay two delivery-priced pizzas for less food than one large. The only time two mediums win is when they are individually discounted enough to beat the large on price per square inch, so always run both through the calculator.
Does crust thickness affect the value calculation?
The price-per-square-inch method compares the top-down area, so it treats a thin-crust and a deep-dish of the same diameter as equal in size even though the deep-dish has far more dough and toppings by volume. For a true food-per-dollar comparison across very different styles you would need to account for thickness. For comparing the same style at different sizes, the area method is accurate and is what this tool uses.