How many pizza do I need for my party?

This is a question we get asked a lot. Of course this is not a precise science and Google hasn't created an algorithm for this yet! But here are a few things to consider that may help.

1. Is pizza your main meal? If you are having just pizza and nothing else you may want to got for the safe option and order 8 or 9 full pizza for every 10 adults and half a pizza for every kid. More on this in the next question. On the other hand if pizza is your "evening food" than it's a safe to assume that a smaller percentage of the guests will want some and they may just eat a few slices, say half a pizza.
2. What's your guests mix? Do you play rugby and most of your friends need 5000 calories a day? Or are your friends more of a standard mix? How many kids are in attendance? If none of your guests skews the average, then refer to question number 1. Age may play a part as well, as naturally older people tend to eat less, especially late in the evening.
3. What time is pizza being served? Is pizza is being served close to lunchtime or early afternoon, people may be very hungry. On the flip side of the coin, if you are hiring a pizza van for the evening, after the weeding breakfast has been served, you may find that your attendees are not that hungry and may just "nibble" on it.

Let us try an put some numbers down. Assuming a typical crowd of 100 people, comprising of
35 ladies - 3/4 of a pizza each
35 man - 1 pizza each
10 kids between 5 and 12 - 1/2 pizza each
20 between gran parents, aunts and uncles - 3/4 pizza each

Total: 81 pizzas