Pizza Size & Value Calculator

A pizza size calculator compares circular pizzas using diameter, quantity and optional prices. It tells you which order has more geometric area and, when both prices are entered, which costs less per unit of area.

The diagram shows one pizza from each option with proportional diameters. The numerical totals include the number of pizzas ordered. This separates a larger individual pizza from a larger combined order.

1. Enter the actual diameter for Pizza A and Pizza B, in inches or centimeters.
2. Set each quantity to the number of pizzas in that option.
3. Enter price per pizza, or leave prices blank to compare area alone.
4. Use one currency for both prices, then review total area and price per square inch or square centimeter.
5. Optionally estimate crust width, swap the options, or copy, print or export the calculation.

The example presets are editable. Switching measurement units converts the physical diameters and crust widths; changing currency formats the same numeric prices without performing an exchange-rate conversion.

For a circular pizza, radius = diameter ÷ 2 and area = π × (diameter ÷ 2)². Circumference, the distance around the edge, is π × diameter.

A 12-inch pizza has radius 6 inches: π × 6² = 113.0973… in², displayed as approximately 113.10 in². A 16-inch pizza has radius 8 inches: π × 8² = 201.0619… in², displayed as approximately 201.06 in².

Total order area = area per pizza × quantity. Total price = price per pizza × quantity. Calculations retain numerical precision internally; only the displayed measurements are rounded.

“Medium” is a restaurant label, not a universal diameter. Check the menu or measure the pizza across its center. Enter that diameter rather than relying on the label.

A 12-inch diameter is used as an editable example here. It does not imply every medium pizza is 12 inches. The same rule applies to small, large and extra-large labels.

The area ratio is (16/12)² = 16/9 ≈ 1.7778. One 16-inch pizza therefore has approximately 77.78% more area than one 12-inch pizza, assuming both are circular.

The diameter is only 33.33% larger, so comparing the diameter percentages alone understates the area difference. The area increase relative to Pizza A is ((area B − area A) ÷ area A) × 100.

Swapping A and B changes that percentage’s baseline. A 12-inch pizza has 43.75% less area than a 16-inch pizza; the two percentages differ because their denominators differ.

Use actual diameters and quantities rather than assuming labels. Two 12-inch pizzas provide 2 × π × 6² ≈ 226.19 in². One 18-inch pizza provides π × 9² ≈ 254.47 in².

The 18-inch pizza has 12.5% more area than the two 12-inch pizzas combined. The “Two 12″ vs one 18″” preset loads that comparison without prices.

More area does not settle monetary value. Enter the per-pizza prices to compare total spending and unit costs. Two medium pizzas could still offer better price-per-area value if their combined price is low enough.

Price per square inch = total price ÷ total area. Lower cost per area is better geometric value when comparing the same currency. Area per currency unit is the reciprocal: total area ÷ total price.

For a 12-inch pizza at an illustrative $12, the unit price is 12 ÷ 113.0973… ≈ $0.1061/in². For a 16-inch pizza at $18, it is 18 ÷ 201.0619… ≈ $0.0895/in². The 16-inch option is approximately 15.63% cheaper per square inch, relative to the 12-inch option’s unit cost.

These prices are examples, not current restaurant offers. The calculator shows a tie when unit prices match and withholds a monetary winner if either price is missing. A zero price is allowed as free; area per currency unit and percentages with a zero-price baseline are shown as undefined where division by zero would occur.

These example diameters use the same circle formula as the calculator. They are not standardized restaurant size categories.

One inch equals exactly 2.54 centimeters, so one square inch equals 6.4516 square centimeters. Use the squared factor to convert area, rather than multiplying by 2.54 once.

Area grows with the square of diameter. Increasing diameter by 50% multiplies area by 1.5² = 2.25, an increase of 125%. Doubling diameter gives four times the area.

Cutting a pizza into more slices changes portion size, not its total area. Thickness, toppings and dough mass are separate measurements, so equal area does not necessarily mean equal food mass or an equal meal.

Quantity changes the total area and price together. Ordering two identical pizzas at the same per-pizza price doubles the area and cost while leaving cost per square inch unchanged.

The optional crust estimate treats the edge as a uniform ring. Inner radius = pizza radius − crust width. Central area = π × inner radius². Crust ring area = total circular area − central area.

For a 12-inch pizza with a 1-inch crust width, the inner radius is 5 inches. Its central area is approximately 78.54 in², and its crust ring is approximately 34.56 in².

Zero width is allowed; width equal to or greater than the radius is rejected. The monetary winner continues to use full pizza area, so the optional geometry does not silently change the comparison basis. Central area is not a measure of topping mass or calories.