Pizza Size Calculator
Settle the 12-versus-16-inch argument with geometry. Enter diameter in inches, how many pies, and the price for two orders — you get total pizza area, cents per square inch for each, and which order is actually the better deal.
Example: with Option A: diameter (in) 12 · Option A: number of pizzas 1 · Option A: price per pizza ($) 12.99 · Option B: diameter (in) 16 · Option B: number of pizzas 1 → How much more pizza: 1.78× — option B (1 × 16 in) has 78% more pizza than option A (1 × 12 in).
- Total area113.1 sq in (A) vs 201.1 sq in (B)
- Cost per square inch11.5¢/sq in (A) vs 8.9¢/sq in (B)
- Better dealOption B — 22.1% cheaper per square inch
Computed by the calculator below using its default values. Change any input to see your own numbers.
Pizza is area: A = π(d/2)² per pie. A 16 in pie is (16/12)² = 1.78 times a 12 in pie — diameter understates the difference because area grows with the square.
Why the big pizza almost always wins
Pizza area grows with the square of the diameter: A = π(d/2)². Going from 12 to 16 inches looks like 33% more pizza but is actually 78% more — 113 vs 201 square inches. Since menu prices rarely rise as fast as area, the price per square inch usually falls as pies get bigger. At $12.99 and $17.99, the 16 in comes out about 22% cheaper per square inch. It is one of the most reliable arbitrage opportunities in food.
The classic gotcha: one 16 in pie (201 sq in) beats two 10 in pies (157 sq in) even though 'two pizzas' sounds like more. Whenever a deal offers two smalls against one large, run the areas before deciding.
When the small pizza is right anyway
Area is not the only variable. Two smaller pies mean two topping configurations, more crust-to-center ratio (crust lovers, take note), and easier leftovers. Edge geometry matters too: a bigger pie has proportionally less rim per square inch of interior, so if you count the rim as wasted, the large gets even better. The math here prices the whole disc — adjust for your crust politics.
How it’s calculated
Each option's total area = quantity × π × (diameter/2)². The comparison ratio is B's total area ÷ A's total area. Cost per square inch = (price per pizza × quantity) ÷ total area, shown in cents. Better deal = lower cost per square inch; the savings percentage is 1 − (cheaper ÷ pricier).
Treats every pizza as a true circle of the stated diameter with equal thickness and toppings — real pies vary an inch and crust thickness shifts the edible fraction.
Round pizza areas (and how they compare to a 10 in)
| Diameter | Area | vs 10 in |
|---|---|---|
| 10 in | 78.5 sq in | 1.00× |
| 12 in | 113.1 sq in | 1.44× |
| 14 in | 153.9 sq in | 1.96× |
| 16 in | 201.1 sq in | 2.56× |
| 18 in | 254.5 sq in | 3.24× |
Computed with A = π(d/2)²; ratios are (d/10)². An 18 in pie is more than three 10 in pies.
Common mistakes
- Comparing diameters instead of areas — 16 vs 12 in is +78% pizza, not +33%.
- Assuming two mediums beat one large: two 10 in pies (157 sq in) lose to one 16 in (201 sq in).
- Forgetting to multiply by quantity when a deal bundles multiple pies.
- Comparing price per pie across different sizes — always divide by square inches first.
Frequently asked questions
What is the formula for pizza area?
A = π × (diameter ÷ 2)². A 14 in pizza is π × 7² ≈ 154 sq in. Because diameter is squared, each 2 in step up adds more area than the previous one.
Is a 16 inch pizza bigger than two 12 inch pizzas?
No — two 12 in pies total 226 sq in, a single 16 in is 201 sq in. But one 16 in does beat two 10 in pies (201 vs 157 sq in). Run the exact quantities in the calculator; intuition is unreliable here.
How do I find the price per square inch?
Total price divided by total area, times 100 for cents. A $17.99, 16 in pizza is 1799 ÷ 201 ≈ 8.9¢ per square inch. Comparing that number across sizes is the only fair way to judge pizza value.
How much more pizza is a 14 inch than a 12 inch?
The ratio is (14/12)² ≈ 1.36, so 36% more pizza from a 2 inch bump — 154 vs 113 square inches. If the 14 in costs less than 36% more, it is the better buy.
Does this account for crust?
No — it prices the full disc. If you skip the rim, subtract about an inch of diameter from each pie before comparing; that adjustment slightly favors larger pizzas, which have proportionally less rim.