Pizza Party Calculator

How many pizzas to order, and which size to buy

Ordering for a crowd comes down to two questions: how many pizzas, and which size gives the most pizza for the money. This pizza party calculator answers both. Enter the adults and children, choose how hungry the group is and how many slices each pizza has, and it gives the number of pizzas, with a split for vegetarian guests and the cost if you enter a price.

The second part compares up to four sizes. Pizza is sold by its diameter, but you eat the area, and area grows with the square of the diameter, so a bigger pizza is often much better value than it looks. The comparison works out the price per square inch and per 100 cm² and flags the best deal. It all runs in your browser.

How to use the Pizza Party Calculator (How Many Pizzas + Best Size)

1. Enter the number of adults and children and pick an appetite: light, average or hungry.
2. Choose the slices per pizza, an extra allowance and the share of vegetarian guests. Add a pizza price for the total cost.
3. To compare sizes, enter the diameter and price of two to four sizes, in inches or centimetres.
4. Read the pizzas to order, and the size with the lowest price per square inch.

Pizza Party Calculator (How Many Pizzas + Best Size) features

How many pizzas per person

A common rule of thumb is about three slices for an adult and two for a child, which is the “average” setting. For 8 adults and 4 children that is 32 slices; with a 10 per cent allowance 35, and with 8-slice pizzas the answer is rounded up to 5 pizzas. Teenagers, a long party or no other food push the number up to four slices an adult; a light snack before a meal brings it down to two. Use the extra allowance for seconds and late arrivals. Left-over pizza keeps well in the fridge.

For a full party menu with starters, mains and drinks, the party food calculator has the quantities for other dishes, including pizza slices.

Why a bigger pizza is often better value

The area of a round pizza is π × (diameter ÷ 2)². A 12-inch pizza has 113 square inches; a 16-inch one has 201, nearly 1.8 times as much, though it is only a third wider. If the 16-inch costs $18 and the 12-inch $12, the large costs 9 cents per square inch and the medium 10.6 cents. Two small pizzas have less pizza than the one large pizza of the same total diameter, so the comparison is worth doing for each menu.

This compares area for the price, not crust thickness: a thin crust and a deep-dish pizza of the same diameter are different amounts of food. To compare other products by weight or volume, the unit price calculator does the same job. To make the pizzas at home instead, try the pizza dough calculator.

Tips for the order

• Mix the toppings. Order a plain cheese pizza for the children and one vegetarian pizza per group of vegetarians.
• Count the slices, not just the pizzas. Some shops cut 6 slices from a medium and 10 from a large.
• Add sides such as salad, garlic bread or dessert, and the pizza needed goes down.
• Allow time: big orders can take longer, so order ahead.