Pizza calculator: how many pizzas do I need?
Enter your guests and how many slices each will eat to see how many pizzas to order. A 14 in large is cut into 8 slices; bigger pizzas are compared by area, not just slice count.
Enter your measurements
More options: Kids · Cut · Extra
- Slices (at this size and cut)
- 64 slices
- Same amount in 14 in large pizzas
- 7.5
- Adults fed per pizza
- 2.7
- Area of one pizza
- 154 sq in (993 cm²)
20 adults × 3 large slices = 60 slices of a 14 in pizza (19.2 sq in each)
= 1,155 sq in ÷ 154 sq in per 14 in pizza = 8 pizzas (64 slices)
Quick answers for common sizes
| Example | Answer |
|---|---|
| How many pizzas for 20 people | 8 pizzas |
| How many pizzas for 30 people | 12 pizzas |
| How many slices in a large pizza | 8 slices |
Pizzas for your guests by size (slices each as above)
| Pizza size | Pizzas to order | Slices (at this size and cut) | Adults fed per pizza |
|---|---|---|---|
| 10 in small | 15 pizzas | 120 slices | 1.4 |
| 12 in medium | 11 pizzas | 88 slices | 2 |
| 14 in large | 8 pizzas | 64 slices | 2.7 |
| 16 in XL | 6 pizzas | 48 slices | 3.5 |
| 18 in | 5 pizzas | 40 slices | 4.4 |
A pizza order is usually a guess based on slices, but slices are not all the same size: a 16 in pizza cut into eight gives slices 30% bigger than a 14 in one cut into eight. So this calculator counts how much pizza each guest eats in slices of a 14 in large — the size Domino’s and most chains cut into 8 — then works out how many pizzas of your size cover that area.
How the pizza count works
pizza needed (sq in) = (guests − ½ × children) × large slices each × 19.2 sq in pizzas = pizza needed ÷ (3.1416 × (diameter ÷ 2)²), rounded up
| Size | Area | Compared with a 14 in large | Adults fed at 3 large slices |
|---|---|---|---|
| 10 in small | 79 sq in | 51% | 1.4 |
| 12 in medium | 113 sq in | 73% | 2 |
| 14 in large | 154 sq in | 100% | 2.7 |
| 16 in XL | 201 sq in | 131% | 3.5 |
| 18 in | 254 sq in | 165% | 4.4 |
How many slices per person?
There is no official figure; it depends on the crowd and what else is on the table. Two large slices each is enough when there are wings, salad and snacks; three is a pizza dinner for adults; teenagers and athletes can manage four. Young children are counted as half an adult. Use the appetite setting to nudge the whole group, and round up — leftover pizza is never wasted.
Worked examples
- How many pizzas for 20 people — a birthday or office party.
- How many pizzas for 30 people — a team party or a class.
- How many slices in a large pizza — and how many people one feeds.
Ordering tips
- Mix the toppings by thirds. For most groups: a third cheese, a third pepperoni, a third something with vegetables or a specialty.
- Ask about the cut. Shops will often cut a large into 12 or square-cut it for kids, which makes the same pizza go further at a children’s party.
- Order a little early. Big orders take longer; ask for it 15 minutes before guests are due to eat.
- Add wings or salad and drop to two slices each: the chicken wings calculator sizes the wings.
What you’ll need
- Heavy-duty paper plates (bulk)Budget price
Sturdy plates that do not fold under a scoop of baked beans. Get small ones too for dessert.
See options on Amazon (opens in a new tab) - Dinner napkins (bulk)Budget price
Napkins go faster than anything else on the table, especially with wings and barbecue.
See options on Amazon (opens in a new tab) - Plastic party cups (16 oz)Budget price
Guests lose track of their cup, so plan two or three per person. A marker by the stack helps.
See options on Amazon (opens in a new tab)
As an Amazon Associate we earn from qualifying purchases. Links to products are affiliate links — they cost you nothing extra and help keep these calculators free.
Frequently asked questions
How many slices are in a large pizza?
Eight, for a 14 in large at most chains — Domino’s lists a hand-tossed large as 1/8 of a pizza per slice. New York style pizzas are often cut into 6 bigger slices. See how many slices in a large pizza.
How many people does a large pizza feed?
About 2 to 3 adults at three slices each, or 4 if each person has two slices with other food. Children eat roughly half as much.
How many pizzas for 10 people?
About 4 large pizzas at three slices each (30 slices, 32 on four pizzas). With wings or salad, 3 is usually enough.
Is a 16 inch pizza better value than two 12 inch pizzas?
Compare by area: a 16 in pizza is about 201 sq in and two 12 in pizzas are about 226 sq in together. Divide the price by the area to compare.
How many pizzas for a kids’ party?
Young children eat about 1 to 2 slices each. Put the number of kids in the children box — each counts as half an adult — or set slices per adult to 1.5 for a party of only kids.
Related guides
Sources
- Domino’s — Nutrition guide (serving sizes by pizza size) (opens in a new tab) — Hand-tossed 12 in medium, 14 in large and 16 in extra large are each listed as 1/8 of a pizza per slice; New York style as 1/6.