Free Pizza Calculators for Parties, Sizes, Dough and Nutrition
Plan a pizza party, find the best-value pizza size, compare delivery deals, make the perfect dough or check the calories in a slice. All 9 of our pizza calculators are free, work on any device and give you an answer in seconds.
Party Pizza
Calculator
Find out exactly how much pizza, slices, sides and drinks your party needs.
Plan My Party →
Pizza Value
Calculator
Compare deals, sizes and prices to see which pizza gives you the most for your money.
Compare Value →
Pizza Dough
Calculator
Calculate exactly how much dough you need for any pizza size and style.
Make My Dough →
Pizza Nutrition
Calculator
Get calorie, protein, carb and fat estimates for your pizza.
Check Nutrition →
Pizza Area
Calculator
See the real surface area of each pizza size so you know exactly how much more pizza you actually get.
Calculate Area →
Pizza Size &
Price Calculator
Enter any pizza's size and price to instantly see the cost per slice and per square inch so you always order the smartest size.
Calculate Size →
How to Work Out How Much Pizza to Order
Ordering pizza for a group should not be a guessing game. Order too little and guests go hungry; order too much and you pay for boxes of leftovers. The guide below explains the simple maths behind our calculators, so you can see exactly how the numbers are worked out.
How many pizzas should you order?
Start with three things: how many people you are feeding, how hungry they are, and what size of pizza you will buy. As a rule of thumb, adults eat about 3 slices, children under 12 eat about 2, and very hungry groups eat more. If pizza is the only food, plan for the higher end; if it is one dish among many, plan for less.
The pizza formula
Pizzas needed = (number of people × slices per person) ÷ slices per pizza, rounded up to a whole pizza.
Example: 10 adults with an average appetite need 10 × 3 = 30 slices. A large 12″ pizza has 10 slices, so 30 ÷ 10 = 3 large pizzas. If the answer comes out at 2.5, round up to 3; a few spare slices are better than hungry guests, and leftovers keep well (see how long pizza lasts in the fridge).
Pizza sizes, slices and servings
Sizes vary between pizzerias, so always check the menu. These are the sizes our calculators use:
| Size | Diameter | Slices | Area | Feeds about |
|---|---|---|---|---|
| Small | 8″ | 6 | 50 in² | 1–2 people |
| Medium | 10″ | 8 | 79 in² | 2–3 people |
| Large | 12″ | 10 | 113 in² | 3–4 people |
| Extra Large | 14″ | 12 | 154 in² | 4–5 people |
Some pizzerias also sell party sizes from 18″ up to 28″ or more. Because area grows with the square of the diameter, a 16″ pizza has about 78% more pizza than a 12″. See our pizza size comparison and how big a 28-inch pizza is.
Tips for ordering pizza for a group
- Count your guests exactly. Separate adults and children, because children eat noticeably less.
- Judge the appetite. Consider the time of day, whether pizza is the main meal or a snack, and whether other food is served.
- Check the crust. Thick and pan crusts are more filling than thin crust, so people eat fewer slices.
- Check slices per pizza. A 12″ pizza may be cut into 8 or 10 slices depending on the pizzeria, which changes how many you need.
- Mix the toppings. Order a mix of cheese, pepperoni and vegetarian pizzas so everyone has an option.
- Compare value before you order. Larger pizzas usually cost less per square inch, but deals and coupons can change that.
Which Pizza Calculator Should I Use?
| If you want to… | Use |
|---|---|
| Order for a mixed group of adults and children | Pizza Party Calculator |
| Order for adults only | Adult Pizza Party Calculator |
| Plan a kids birthday or school party | Kids Pizza Party Calculator |
| Find the best-value pizza size | Pizza Size & Price Calculator |
| Compare delivery deals | Pizza Value Calculator |
| Compare the area of different pizzas | Pizza Area Calculator |
| Work out what homemade pizza costs | Pizza Cost Calculator |
| Get a dough recipe for any size | Pizza Dough Calculator |
| Estimate calories per slice | Pizza Nutrition Calculator |
Pizza Calculator FAQs
Are these pizza calculators free?
Yes. All of our pizza calculators are free to use, need no sign-up and work on phones, tablets and computers.
How many pizzas do I need for 20 people?
For 20 adults with an average appetite, plan on about 60 slices: 6 large 12″ pizzas (10 slices each) or 5 extra-large 14″ pizzas (12 slices each). Use the Pizza Party Calculator to adjust for children and appetite.
How many slices are in a large pizza?
A large 12″ pizza is usually cut into 8 or 10 slices, and a 14″ pizza into 10 or 12. Read how many slices are in a 12-inch pizza for more detail.
Is it cheaper to buy one large pizza or two medium pizzas?
One large pizza is usually better value, because area grows faster than price. Two 12″ pizzas (226 in²) do have more pizza than one 16″ (201 in²), though, so compare real prices in the Pizza Size & Price Calculator.
