Pizza Size Comparison Calculator
Compare two pizza sizes by area and value per square inch.
Enter diameters and prices to find out which size is the better deal based on actual pizza area.
Pizza area follows the standard circle area formula, and the math reveals some surprising facts about value that most pizza buyers never realize.
Circle area formula:
Area = π × r²
Where r = radius = diameter ÷ 2, and π ≈ 3.14159.
Or equivalently: Area = π × (diameter / 2)²
Why size matters so much more than it looks: Because area scales with the square of the radius, a small increase in diameter creates a much larger increase in area. A 16-inch pizza is not 33% bigger than a 12-inch pizza — it is 78% bigger.
Pizza size reference table:
| Size Label | Diameter | Area | Slices (typical) | vs. 12" |
|---|---|---|---|---|
| Personal | 6" | 28 sq in | 4 | 0.25× |
| Small | 8" | 50 sq in | 6 | 0.44× |
| Medium | 10" | 79 sq in | 6–8 | 0.69× |
| Large | 12" | 113 sq in | 8 | 1.00× |
| XL | 14" | 154 sq in | 10 | 1.36× |
| XXL | 16" | 201 sq in | 10–12 | 1.78× |
| Party | 18" | 254 sq in | 12 | 2.25× |
The classic pizza math trick: One 18-inch pizza contains more pizza than two 12-inch pizzas.
- Two 12" = 226 sq in of pizza
- One 18" = 254 sq in of pizza
- Plus, one large pizza is almost always priced lower than two mediums
Cost per square inch — the real value metric:
Price per sq in = Price / Area
A $12 medium (12") = $0.106/sq in A $16 large (16") = $0.080/sq in — 25% cheaper per bite
Worked example — comparing two pizzas: Pizza A: 12" diameter, $11.99 Pizza B: 14" diameter, $14.99
- Area A = π × 6² = 113.1 sq in → $0.106/sq in
- Area B = π × 7² = 153.9 sq in → $0.097/sq in
Pizza B is the better value by 8.5% per square inch.
Toppings note: Topping density matters too. A thin-crust pizza stretched to 16" may have fewer toppings per square inch than a thicker 12".