Quick answer
Pizza area = π/4 × diameter², and value = area ÷ price. A 12-inch pizza at $10 gives 11.31 square inches per dollar, a 16-inch at $15 gives 13.4, so the larger pizza is better value.
Enter the diameter and price of two pizzas. The calculator returns area per dollar and which is the better deal. It is a pizza size comparison that shows which pizza gives more food per dollar.
Related tools: Pizza Calculator: Number of pizzas for a group.
How to use the Pizza Size Comparison Calculator
- Enter pizza 1 diameter (in) (above 0).
- Enter pizza 1 price ($) (above 0).
- Enter pizza 2 diameter (in) (above 0).
- Enter pizza 2 price ($) (above 0).
- Press Calculate to see the result, and use Reset to start again.
| Input | What to enter | Allowed values |
|---|---|---|
| Pizza 1 diameter | A number, in in | > 0 |
| Pizza 1 price | A number, in $ | > 0 |
| Pizza 2 diameter | A number, in in | > 0 |
| Pizza 2 price | A number, in $ | > 0 |
Formula and method
Formula
area = π/4 × d²; value = area ÷ price
IEEE-754 double precision; shown to the decimals indicated.
Compares surface area only, not crust thickness or toppings.
Worked examples
These examples are verified: each one is an automated test case that the live calculator must reproduce exactly.
Example 1
Inputs: Pizza 1 diameter = 12; Pizza 1 price = 10; Pizza 2 diameter = 16; Pizza 2 price = 15.
| Result | Value |
|---|---|
| Better value | Pizza 2 |
| Pizza 1: sq in per dollar | 11.31 |
| Pizza 2: sq in per dollar | 13.4 |
Example 2
Inputs: Pizza 1 diameter = 10; Pizza 1 price = 8; Pizza 2 diameter = 10; Pizza 2 price = 9.
| Result | Value |
|---|---|
| Better value | Pizza 1 |
| Pizza 1: sq in per dollar | 9.82 |
| Pizza 2: sq in per dollar | 8.73 |
The first line is the headline result (better value). Below it the pizza Size Comparison Calculator lists pizza 1: sq in per dollar and pizza 2: sq in per dollar, which describe the same case from other angles. IEEE-754 double precision; shown to the decimals indicated.
Area grows with the square
A 16-inch pizza has (16 ÷ 12)² = 1.78 times the area of a 12-inch pizza, though the diameter is only 1.33 times larger. That is why the larger size is often a better deal, and why the 'one big' option can hide a bigger price premium.
Thickness and toppings
Deep-dish crusts and extra toppings change how much food you get per square inch. The calculator compares area only.
How the result changes with pizza 1 diameter
Holding every other input at the first worked example, this table changes only pizza 1 diameter. It shows how sensitive the answer is to that one value; each row was produced by running this calculator.
| Pizza 1 diameter | Better value | Pizza 1: sq in per dollar | Pizza 2: sq in per dollar |
|---|---|---|---|
| 6 | Pizza 2 | 2.83 | 13.4 |
| 12 | Pizza 2 | 11.31 | 13.4 |
| 24 | Pizza 1 | 45.24 | 13.4 |
| 48 | Pizza 1 | 180.96 | 13.4 |
What happens with invalid input
These messages are produced by the calculator itself, so you know what to fix.
- Pizza 1 diameter: entering "0" shows "Pizza 1 diameter must be greater than 0." beside that field and no result.
- Pizza 1 price: entering "0" shows "Pizza 1 price must be greater than 0." beside that field and no result.
Choosing between the Pizza Size Comparison Calculator and similar calculators
Each row shows what a related calculator on this site asks for and what it returns, so you can pick the one that matches your question.
| Calculator | You enter | It returns |
|---|---|---|
| [Pizza Calculator](/lifestyle/pizza-calculator/) | people, slices per person and slices per pizza | Pizzas to order |
| [Turkey Size Calculator](/lifestyle/turkey-size-calculator/) | guests and turkey per person | Turkey needed |
| [Ham Size Calculator](/lifestyle/ham-size-calculator/) | guests and ham per person | Ham needed |
| [Tire Size Comparison Calculator](/automotive/tire-comparison-calculator/) | old tire: Section width, old tire: Aspect ratio and old tire: Rim diameter | Diameter difference |
| [Height Comparison Calculator](/lifestyle/height-comparison-chart/) | person A and person B | Height difference |
Assumptions and limitations
- Area grows with the square of diameter
If a required value is empty, not a number, or outside its allowed range, the form marks that field with a message and shows no result instead of a misleading number. The automated checks deliberately try invalid entries for pizza 1 diameter and pizza 1 price to confirm this.
Frequently asked questions
Are two 12-inch pizzas better than one 18-inch?
No: two 12-inch pizzas total about 226 square inches, while one 18-inch pizza has about 254, so the single large pizza gives more food for the area.
Does the crust count?
Yes, area includes the edge.
Can I compare square pizzas?
Use the area directly.
What does the Pizza Size Comparison Calculator calculate?
Which pizza gives more area per dollar. It returns Better value, Pizza 1: sq in per dollar and Pizza 2: sq in per dollar.
What formula does the Pizza Size Comparison Calculator use?
area = π/4 × d²; value = area ÷ price. Compares surface area only, not crust thickness or toppings.
What do I need to enter in the pizza Size Comparison Calculator?
You enter Pizza 1 diameter (in), Pizza 1 price ($), Pizza 2 diameter (in) and Pizza 2 price ($).
How is the result rounded or limited?
IEEE-754 double precision; shown to the decimals indicated. Area grows with the square of diameter.
What is an example of a pizza Size Comparison result?
With pizza 1 diameter 12, pizza 1 price 10, pizza 2 diameter 16 and pizza 2 price 15, the better value is Pizza 2.
Related calculators
- Pizza Calculator — Number of pizzas for a group.
- Tire Size Comparison Calculator — Compare two tire sizes and the resulting speedometer error.
- Height Comparison Calculator — Difference and ratio between two heights.
- Tire Size Calculator — Overall diameter, sidewall height and revolutions per mile from a tire size such as 225/45R17.
Sources
- OpenStax, Prealgebra 2e (Rice University): fractions, decimals, percents, ratios and rounding
Content last reviewed 2026-11-04. Formulas and worked examples are checked by automated tests against independently computed values.