Pizza Size Comparison Calculator
Compare two pizzas by area and by price per square inch to see which is better value.
Last updated · View algorithm, constants and default inputs (JSON)
Comparison
About this calculator
Pizza value is a question of area, not diameter. Because area scales with the square of the diameter, one 18-inch pizza is larger than two 12-inch pizzas, even though the total diameter is smaller.
Worked example
calculated with the default values below
Pizza 1 diameter 12 in · Pizza 1 price 12 $ · Pizza 2 diameter 18 in · Pizza 2 price 20 $ Pizza 1 area 113.1 in² · Pizza 2 area 254.5 in² · Pizza 2 ÷ pizza 1 area 2.25 x · Pizza 1 price per in² 0.1061 $ · Pizza 2 price per in² 0.0786 $ · Better value Pizza 2
General background references
Disclaimer
These calculators give general cooking guidance. Ingredient density, oven calibration, altitude and equipment all vary, and safe minimum internal temperatures always take precedence over timings. Follow the food-safety advice issued by your national authority.
Implementation source
This record describes the implementation used by this page. It is not independent validation. External references, when available, support only the stated formula or definition; estimates and custom rules retain their own assumptions.
Formula and variables
A = π × (d ÷ 2)^2; r = A₂ ÷ A₁; P_a = P ÷ A
- A
- Pizza area (in²)
- d
- Diameter (in)
- r
- Area ratio (2 vs 1)
- P_a
- Price per area
The pizza with the lower price per area wins.
Frequently asked questions
Why is one 18-inch pizza larger than two 12-inch pizzas?
Area scales with the square of the diameter, so the tool reports area ratio directly. A single 18-inch pie has area pi*9^2 ≈ 254 sq in, while two 12-inch pies total 2*pi*6^2 ≈ 226 sq in, so the one large pizza is about 1.13 times bigger despite a smaller combined diameter. At the defaults the 18-inch at $20 costs $0.079 per sq in versus $0.106 for the 12-inch at $12, making the larger pie the better value too.