Pizza Calculator: How Many Pizzas to Order and Which Size Is Cheaper
Enter the group size and slices per person to find the number of pizzas. Then enter two sizes and prices to see which gives more pizza for your money.
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Formula
- Slices needed:
people x slices per person, rounded up - Pizzas:
slices needed / slices per pizza, rounded up - Area:
pi x (diameter / 2)^2 - Price per square inch:
price / area
Worked example
8 people x 3 slices = 24 slices, divided by 8 = 3 pizzas.
| Size | Area | Price | Per sq in |
|---|---|---|---|
| 14 in | 153.94 sq in | 12 | 0.078 |
| 18 in | 254.47 sq in | 20 | 0.079 |
The 14 in pizza is slightly cheaper per square inch, while the 18 in pizza has 1.65 times the area.
Frequently asked questions
How many pizzas do I need for 8 people?
At 3 slices each that is 24 slices, and with 8 slices per pizza you need 3 pizzas. Always round up so nobody goes short.
Is a bigger pizza really better value?
Usually, because area grows with the square of the diameter. An 18 in pizza has 254.5 sq in, 1.65 times a 14 in pizza (153.9 sq in), though it does not cost 1.65 times as much.
How do I calculate price per square inch?
Divide the price by the area, pi x (diameter / 2)^2. A 14 in pizza at 12 is 12 / 153.94 = 0.078 per sq in.
How many slices should I plan per person?
Two to three slices for adults is typical, and about one to two for children. Raise it for a pizza-only meal, lower it if there are other dishes.