Pizza Size Calculator
Compare pizza sizes before choosing an order for a group. Result: first pizza area from the entered values.
How the result changes
Only first pizza diameter changes; all other inputs stay at your current values. The line illustrates the formula across the shown range. This is not a forecast of real-world outcomes.
About this calculation
Pizza Size Calculator calculates first pizza area from first pizza diameter, second pizza diameter. Compare pizza sizes before choosing an order for a group. The main answer uses sq in and follows the specific assumptions explained below.
Formula
Circular pizza area = π × (diameter ÷ 2)²; area ratio = (second diameter ÷ first diameter)².
Worked example
With First pizza diameter: 12 in, Second pizza diameter: 16 in, first pizza area is 113.097336 sq in.
Inputs and calculation
Halve each stated diameter to get its radius, square the radius and multiply by pi. Divide the second area by the first to compare how much circular surface each pizza offers. The displayed relationship is Circular pizza area = π × (diameter ÷ 2)²; area ratio = (second diameter ÷ first diameter)². Keep the fields' displayed units attached when reproducing this relationship by hand.
Worked numerical example
For example, enter first pizza diameter 12 in, second pizza diameter 16 in. Those inputs produce first pizza area of 113.1 sq in. The same values also give second pizza area 201.06 sq in; second-to-first area ratio 1.7778 ×.
Holding the other example values fixed, change first pizza diameter from 12 to 13.2 in. The main output becomes 136.85 sq in. This comparison isolates the effect of that one input.
How to read and use the result
The diameter ratio alone understates the size difference because area grows with the square of diameter. A 16-inch pizza has more than one third extra area compared with a 12-inch one. Compare pizza sizes before choosing an order for a group.
Practical context
A 12-inch pizza has about 113.1 square inches of circular area; a 16-inch pizza has about 201.1. The second is roughly 1.78 times the first despite its diameter being only 1.33 times as large.
Assumptions and scope
Both pizzas are approximately round and measured edge to edge. The comparison treats the full disk as edible area and does not remove crust thickness or missing slices. Replace the example defaults with measured inputs for your situation and account separately for factors outside these fields.
Checks and common mistakes
Do not assume two 8-inch pizzas have the same area as one 16-inch pizza. If prices differ, compare area per price rather than diameter per price.
Common questions
What should I verify before using the Pizza Size Calculator result?
If each pizza has a thick crust border, the edible topping area follows a smaller inner radius and the simple full-disk comparison changes. Price per square inch can be useful, but topping quantity and the number of diners matter too.
Inputs
- First pizza diameter (in)
- Second pizza diameter (in)