Pizza calculator

Enter your guests and pizza size to see how many pizzas to order, with a safe and a lean number and what's likely left over.

Count teens as adults. They often eat more.
Appetite
Average is about 3 slices per adult and 2 per kid. Pick Hungry for teens, game day, or when pizza is dinner after sports.
Fills in a common cut for the size: 6 for small, 8 for medium and large, 12 for extra large. Pizzerias cut differently, so change it if yours does.
Other food at the party?
Wings, salad, chips, or cake mean people eat about a quarter less pizza.

Pizzas to order

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Enter how many people are coming.

These are estimates. Appetites vary a lot from crowd to crowd. When in doubt, order the safe number. Leftover pizza keeps, but running out doesn't.

How we calculated this

Each guest gets a slice count based on appetite. Slice counts are for a typical large slice, which is one-eighth of a 14" pizza:

  • Light: 2 slices per adult, 1.5 per kid
  • Average: 3 slices per adult, 2 per kid
  • Hungry: 4 slices per adult, 3 per kid

If there's other food, the total drops by 25%.

Small pizzas have much less pizza than large ones. A 16" pizza is about 2.5 times the size of a 10". So instead of counting slices alone, the calculator converts the total into square inches of pizza and divides by the size of the pizza you picked. Slices per pizza only change how many of your slices that works out to and how many are left over.

The main number is rounded up to a whole pizza. Lean is about 15% less food than the estimate, and might run short if people are hungry. Safe is about 20% more, and always at least one more pizza than the main number.

Sources and where they disagree

There's no official standard for this, so these are rules of thumb from catering guides, pizza chains, and calculators. They broadly agree on 3 slices per adult and 2 per kid, but not on the details.

  • 3 slices per adult and 2 per kid: Tasting Table and Omni Calculator's pizza party tool. Omni bases its 3 slices on a medium pizza, while others assume a large, so a "slice" is not the same size everywhere.
  • Other food changes the answer: a Domino's guide (Norway) suggests 2 to 3 slices per person with other food, 3 to 4 for a birthday party, and 4 to 6 when pizza is the whole meal. That's higher than most US guides.
  • Some guides, such as Instacart's pizza calculator, suggest adding an extra slice per person for thin crust or when pizza is the main meal.
  • Slices per size: Food Republic and Pequod's show that cuts vary. A 14" is cut into 8 at many chains but 10 at others, and a 16" can be 8, 10, or 12. That's why you can change the slice count.

Pizza area is worked out as a circle (π × radius²), so a 14" pizza is about 154 square inches and one-eighth of it is about 19 square inches.

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Figures and sources last reviewed November 2026.