# Estimating Crowd Sizes

Discussion | **Summary** | Extension | Practice

# The Gist of Things

In general, 10 people can fit in a 25 square feet box. If we divide the number of people by the total area, we find that **one person takes up about 2.5 squared feet of space.**

This number is the

**occupant load factor**- the amount of space one person is assumed to take up.**This number can change depending on context.**Unless an occupant load factor is given, assume it is 2.5 squared feet per person.

## What To Do

Using this information, we can do the following to find the crowd size:

**Let an area of some space (a room, a sidewalk, etc.) be taken up completely by a group of people.**

Find the area of that space

Divide that space by our occupant load factor

Define your answer with units (we're not counting tractors or dogs - we're counting humans.

Below: An excerpt of NFPA 101, giving different occupant load factors depending on context.

The idea, however, is the same - one person takes up *x* amount of space.