Pizza Size Calculator
Compare pizza sizes by area and price per square inch to find the best value.
Written by Golam Rabbani, Founder & Lead Engineer
How to use this pizza size calculator
- Pick the diameter unit — inches or centimeters.
- Enter the diameter and optional price for each pizza you want to compare.
- Press Add pizza to add another size to the comparison; press the × button to remove one.
- Hit Calculate to see each pizza's area, $/sq-in, and which one is the best value.
- Use Copy to grab the result or Reset to start over.
About this pizza size calculator
A pizza is a circle, and the area of a circle grows with the square of its radius (A = π × r²). That makes diameter wildly misleading when comparing prices: a 16-inch pizza is not twice as big as an 8-inch — it is four times as big. The pizza size calculator does that area math for you and shows the per-square-inch price so you can spot the genuine bargain.
Worked example: a 12-inch pizza has area π × 6² ≈ 113.1 sq in. A 16-inch pizza has area π × 8² ≈ 201.1 sq in. If the small is $12 and the large is $18, the small costs $0.1061 per square inch and the large costs $0.0895 per square inch — so the 16-inch is the better deal even though it sounds 1.3× the price of the small. The tool also reports the combined area (113.1 + 201.1 = 314.2 sq in, equivalent to one round pizza of about 20 inches) so you can see how much pizza you are actually buying.
FAQ
- Why is comparing pizzas by area better than by diameter?
- Because area scales with the square of diameter. Doubling the diameter quadruples the pizza. A 16-inch pizza has nearly four times the area of an 8-inch, so per-square-inch price is the only fair value metric.
- How is price per square inch calculated?
- Price ÷ (π × (diameter ⁄ 2)²). The tool computes this for every pizza you enter and highlights the lowest number with a star — that is the best value.
- Can I compare a one-large vs two-medium decision?
- Yes — enter both pizzas and the calculator shows the combined area and a single equivalent-diameter pizza for them. That lets you see whether two mediums actually beat one large in raw pizza.
- Do I have to enter prices?
- No. If you only want to compare sizes (area and equivalent diameter), leave prices blank. The price-per-square-inch column will simply show a dash.
- Does the calculator support metric sizes?
- Yes. Switch the diameter unit to cm; the tool converts to inches internally (1 in = 2.54 cm) so the math stays consistent and the area output stays in square inches.
- Is the pizza size calculator free?
- Yes. It runs entirely in your browser, has no signup, and never sends your inputs anywhere.