Plot No. 36 · Everyday & Shopping
Pizza Size Value Calculator
Compare two pizzas by price per square inch to see which is the better deal. The area of a round pizza is pi times the radius squared, then price divided by area gives the cost per square inch. A 10 inch at 9.99 costs more per inch than a 14 inch at 14.99, so the larger pizza is about 23.4 percent better value.
Pizza A
Pizza B
Value is compared by area, since pizza area grows with the square of the diameter. This ignores crust thickness and toppings.
The link saves your inputs so you can bookmark or share this exact result.
Pizza size chart: how many square inches in each size
A menu lists pizzas by diameter, but what you eat is the area, which is pi times the radius squared. The radius is half the diameter, so a 12 inch pizza is pi times 6 squared, or 113.1 square inches. Because the radius is squared, the food climbs much faster than the width: a 20 inch pizza is twice the diameter of a 10 inch but 4.00 times the pizza.
| Diameter | Radius | Area (sq in) | Area (sq cm) | Versus a 10 inch |
|---|---|---|---|---|
| 6 in | 3 in | 28.3 | 182 | 0.36x |
| 8 in | 4 in | 50.3 | 324 | 0.64x |
| 10 in | 5 in | 78.5 | 507 | 1.00x |
| 11 in | 5.5 in | 95.0 | 613 | 1.21x |
| 12 in | 6 in | 113.1 | 730 | 1.44x |
| 14 in | 7 in | 153.9 | 993 | 1.96x |
| 16 in | 8 in | 201.1 | 1,297 | 2.56x |
| 18 in | 9 in | 254.5 | 1,642 | 3.24x |
| 20 in | 10 in | 314.2 | 2,027 | 4.00x |
Two smaller pizzas versus one larger one
Two boxes look like more food than one, and sometimes they are, but the answer flips depending on the exact pair. Two 12 inch pizzas beat a single 16 inch by area, yet the same two lose to one 18 inch. These rows compare total area only, so they answer which option is more pizza. Which one is better value also depends on price, and that is what the calculator above settles.
| The smaller option | Total area | The larger option | Area | More pizza |
|---|---|---|---|---|
| 2 x 8 in | 100.5 | 1 x 12 in | 113.1 | 1 x 12 in, by 12.5% |
| 2 x 10 in | 157.1 | 1 x 14 in | 153.9 | 2 x 10 in, by 2% |
| 2 x 10 in | 157.1 | 1 x 16 in | 201.1 | 1 x 16 in, by 28% |
| 2 x 12 in | 226.2 | 1 x 16 in | 201.1 | 2 x 12 in, by 12.5% |
| 2 x 12 in | 226.2 | 1 x 18 in | 254.5 | 1 x 18 in, by 12.5% |
| 2 x 14 in | 307.9 | 1 x 20 in | 314.2 | 1 x 20 in, by 2% |
| 3 x 10 in | 235.6 | 1 x 18 in | 254.5 | 1 x 18 in, by 8% |
Is the upsize worth it? The break-even price for each step
Going up a size is worth it whenever the extra pizza outruns the extra cost. Since the area ratio between two sizes is fixed, so is the price at which the two are exactly equal value. Going from 12 inch to 16 inch gives you 1.78 times the pizza, so the 16 inch is the better deal at any price under 1.78 times the 12 inch. The last column puts that in cash by assuming the smaller pizza costs £10.00. Swap in the prices on your own menu with the calculator above.
| Upsize | Extra pizza | Break-even price ratio | Smaller at £10.00, larger worth up to |
|---|---|---|---|
| 10 in to 12 in | 44% | 1.44x | £14.40 |
| 10 in to 14 in | 96% | 1.96x | £19.60 |
| 12 in to 14 in | 36.1% | 1.36x | £13.61 |
| 12 in to 16 in | 77.8% | 1.78x | £17.78 |
| 14 in to 16 in | 30.6% | 1.31x | £13.06 |
| 14 in to 18 in | 65.3% | 1.65x | £16.53 |
| 16 in to 18 in | 26.6% | 1.27x | £12.66 |
| 18 in to 20 in | 23.5% | 1.23x | £12.35 |
Every figure on this page is computed from the area formula rather than typed in, so the tables match the calculator exactly. They compare flat round pizzas and ignore crust thickness, toppings and how much of the edge you actually eat. For the geometry on its own see the circle calculator, and for the same price-per-unit test on anything else sold by size there is the unit price calculator.
How the pizza value is worked out
A round pizza's area is pi times the radius squared, where the radius is half the diameter. This calculator works out each pizza's area, then divides the price by the area to get a cost per square inch, and compares the two. A 10 inch pizza has an area of about 78.5 square inches, and a 14 inch about 153.9 square inches.
Because area grows with the square of the diameter, a slightly bigger pizza usually carries far more food than its price suggests. A 10 inch at 9.99 works out to about 0.127 per square inch, while a 14 inch at 14.99 is about 0.097 per square inch, so the 14 inch is roughly 23.4 percent better value despite costing 5 more.
How to use the pizza value calculator
- Enter the diameter and price of the first pizza.
- Enter the diameter and price of the second pizza.
- Read which pizza is the better deal and by what percentage, along with each area and price per square inch.
Worked examples
Small versus large
Inputs: Pizza A 10 inch for 9.99, Pizza B 14 inch for 14.99
Result: A is about 0.127 per square inch, B about 0.097, so B is the better deal by roughly 23.4 percent.
Two for one deal check
Inputs: Pizza A 12 inch for 10.00, Pizza B 18 inch for 18.00
Result: A is about 0.0884 per square inch, B about 0.0707, so the 18 inch is about 20 percent better value even at nearly double the price.
Limitations and common mistakes
Edge cases and limitations
- It compares flat area only and ignores crust thickness, depth and the amount of topping.
- Square or rectangular pizzas are not covered, since this assumes a circle.
- It does not weigh up whether you will actually eat the extra, only the value per square inch.
Common mistakes
- Judging value by diameter alone, when doubling the diameter quadruples the area.
- Entering the radius instead of the full diameter, which understates the area fourfold.
Frequently asked questions
Is a bigger pizza better value?
Almost always, because area grows with the square of the diameter. A 14 inch pizza has nearly twice the area of a 10 inch one (153.9 versus 78.5 square inches), so unless the big one costs nearly double, it is the better deal per bite.
How do you compare two pizza sizes?
Work out each pizza's area as pi times the radius squared, then divide the price by the area. A 10 inch at 9.99 is about 0.127 per square inch, while a 14 inch at 14.99 is about 0.097, so the 14 inch wins by roughly 23.4 percent.
Why does doubling the diameter more than double the pizza?
Because pizza is measured by area, not width. Doubling the diameter quadruples the area, since area depends on the radius squared. A 16 inch pizza has four times the topping and base of an 8 inch, not twice.
How many square inches is a 12 inch pizza?
About 113.1 square inches. The radius is half the diameter, so 6 inches, and the area is pi times 6 squared, which is 113.1 square inches or roughly 730 square centimetres. For the other common sizes: a 10 inch is 78.5, a 14 inch is 153.9, a 16 inch is 201.1 and an 18 inch is 254.5 square inches.
Is two 12 inch pizzas bigger than one 16 inch?
Yes. Two 12 inch pizzas come to about 226.2 square inches against 201.1 for a single 16 inch, so the pair gives you around 12.5 percent more pizza. Go one size up though and it flips: one 18 inch is 254.5 square inches, which beats the same two 12 inch pizzas.
How much bigger is a 16 inch pizza than a 12 inch?
About 78 percent bigger, not 33 percent. The diameter is a third larger but the area scales with the square of that ratio, so 16 divided by 12 is 1.33 and 1.33 squared is 1.78. That is also the break-even price: the 16 inch is the better value as long as it costs less than 1.78 times the 12 inch.
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