How to use the pizza size comparison calculator
- Choose whether you measured the pizzas in inches or centimeters.
- List each pizza with a name, its diameter, its price and how many you would get. Two example pizzas are filled in. Add up to 8.
- Use the how many column to compare buying two of one size against one of another.
- Read the best value, the cost per square inch or centimeter for each pizza, and the table that also shows each area compared with the smallest. Use Copy, Print or CSV to keep it.
Formula
Area of one round pizza = pi x (diameter / 2)^2
Total area = area of one pizza x how many
Cost per area = total price / total area
Area compared with the smallest = total area / smallest total area
Pizza size is given as a diameter, but what you eat is the area, which grows with the square of the diameter. Doubling the diameter gives four times the pizza.
A 12 inch pizza and a 16 inch pizza
A 12 inch pizza at $14 has an area of pi x 6^2 = 113.1 square inches, or $0.1238 per square inch. A 16 inch pizza at $20 has an area of pi x 8^2 = 201.1 square inches, or $0.0995 per square inch.
The 16 inch pizza has 177.8% of the area of the 12 inch one (16 squared over 12 squared is 256 / 144), for $6 more. It costs 19.6% less per square inch, so it is the better value. Switch to centimeters and two 30 cm pizzas at $12 each are 1,413.7 square centimeters for $24, which is $0.0170 per square centimeter, 200% of one 30 cm pizza.
Why bigger often means better value
The diameter makes a pizza look only a little larger, yet the area jumps. Going from 12 to 16 inches adds a third to the width but nearly doubles the area. Pizza places usually raise the price by less than the area, so larger sizes usually cost less per square inch. The calculator turns that into a number you can compare.
Value is not only about area. The thickness of the crust, the amount of toppings and the way a pizza is cut change how much you eat. A thick crust pizza may have less topping per square inch. Treat the cost per area as one input.
Ordering for a group
To decide how much to order for a group, use the how many column. Two medium pizzas against one large, or three small ones against two large ones, can have very different areas for the same money. Pair the area with the number of slices each person usually eats to work out the order.
For other food planning, try the party food and drink calculator and the catering cost per head calculator. Use the unit price calculator for other products sold in different sizes and the circle calculator for the area of any round object.
Assumptions and limits
- All pizzas are round, and the diameter is the size of the finished pizza, including the crust.
- Prices are the examples or the amounts you enter, before tax, delivery and tip.
- Crust thickness, toppings and slice count are not compared.
- Cost per area is shown with four decimal places so close prices can be told apart.
Frequently asked questions
How do I compare pizza sizes?
Work out the area of each with pi times the radius squared, then divide the price by the area. The lowest cost per square inch is the best value.
Is a 16 inch pizza twice the size of an 8 inch pizza?
It has four times the area. Doubling the diameter multiplies the area by two squared, which is four.
Can I compare two small pizzas to one large?
Yes. Put 2 in the how many column for the small size. The tool multiplies area and price together.
What if my pizza is square or rectangular?
This tool is for round pizzas. For a rectangle, multiply the length by the width to get the area and divide the price by it yourself, or use the area calculator.