Pizza Party Calculator: How Many Pizzas to Order, Leftovers and Cost
Work out how many pizzas to order for a party from the number of adults and kids, appetite and slices per pizza, with leftovers, a separate count for vegetarian or special-diet guests, total cost and cost per guest.
How it works
slices eaten = adults × slices per adult + children × slices per child · pizzas = round up (slices eaten × (1 + margin) ÷ slices per pizza) · leftovers = pizzas × slices per pizza − slices eaten · cost = pizzas × price + fees + tip
Multiply each group of guests by how many slices they will eat, add them up, divide by the slices in one pizza and round up, since you cannot order part of a pizza. The appetite levels follow common pizzeria planning figures: about 3 slices for an average adult and 2 for a child, fewer when other food is served and more when pizza is the whole meal or the crowd is teenagers or athletes. Rounding up is what creates the leftover slices, which the calculator shows so you know how much spare you are buying. Under More options you can split off guests who need their own pizza (vegetarian, gluten-free, allergy) so their slices are counted on separate pizzas, add a safety margin, and include delivery fees and a tip in the cost. The tables compare all four appetite levels and give a quick count for other party sizes. A standard 14 in large pizza is usually cut into 8 slices; change the slices field if your pizzeria cuts differently.
Worked example
10 guests with an average appetite eat 3 slices each: 10 × 3 = 30 slices. At 8 slices per pizza that is 30 ÷ 8 = 3.75, rounded up to 4 pizzas (32 slices), leaving 2 slices over, or 3.2 slices per guest. At $15 a pizza the order costs 4 × $15 = $60.00, or $6.00 per guest.
Sources: Pizza Hut: Pizza calculator (adults, children, 8 slices per pizza) · Inch Calculator: Pizza calculator (3 slices per adult, 2 per child) · Omni Calculator: Pizza party calculator (slices by pizza size)
Frequently asked questions
How many slices of pizza does each person eat?
About 3 slices of a standard large pizza is the usual planning figure for an adult and 2 for a child. When there are lots of other snacks, plan on 2; when pizza is the whole meal for teens or a hungry crowd, plan on 4 or 5.
How many pizzas do I need for 20 people?
With an average appetite (3 slices each) 20 adults eat 60 slices. At 8 slices per pizza that is 7.5, so order 8 pizzas and you will have 4 slices spare. A light crowd (2 slices each) needs 5 pizzas.
How many pizzas for 10 kids?
Children usually eat about 2 slices each, so 10 kids need 20 slices: 3 pizzas of 8 slices with 4 left over. For a light snack, 1 slice each, 2 pizzas are enough.
Should I round up or down?
Always up. Running out is worse than a few leftovers, and cold pizza keeps well. The calculator rounds up for you and shows the spare slices.
Do different pizza sizes change this?
Yes. Set the slices-per-pizza field to match: a 10 in small is often 6 slices, a 14 in large 8 (some pizzerias cut 10) and a 16 in extra-large 10 or 12. Bigger pizzas with more slices feed more people per box, but thinner slices mean guests take more of them.
How do I handle vegetarian or gluten-free guests?
Enter how many need a separate pizza under More options. Their slices are counted on their own pizzas, and the rest of the order covers everyone else, so the special pizzas do not get eaten first.
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This calculator is for educational purposes. Double-check important results before acting on them.