So how many people will that room hold anyway…?

Many experienced planners can just look at a meeting room and make a fairly accurate estimate of its capacity (without looking at a capacity chart) – which is, admittedly, a cool trick. But how do they do it and how do they know how large a room they need to begin with? They had to figure it out somehow, right? Right. Well, it all comes down to math…

Different room sets use different amounts of space and there are generally accepted guidelines as to how much space is needed per person for each type of seating. So, once you know how many square feet a room contains, it is a fairly easy matter to then figure out how many people it will hold. For instance, I assume that I will need 15 square feet of space for each person attending a banquet. If the room is 4,000 square feet, then I figure I should be able to get about 260-270 people in comfortably. This (very rough!) estimate includes space for servers to access the tables once diners are seated, space for people to sit and move about easily, exit aisles, and so forth. I also include space for the common audio-visual equipment that might be needed for the program in my estimate since I would rather have slightly too much space for my group than not enough. Great. So what about other types of seating? Here are the approximations I most frequently use:

Banquet (60” or 72” rounds): 15 square feet/person
Classroom (18” tables): 15 square feet/person
Classroom (30” tables): 20 square feet/person
Theater or Reception: 10 square feet/person
Hollow Square: 40 square feet/person

It is important to note that these are not formal space requirements. I’ve rounded up the industry standards so as to make the math easier for me to do a quick estimate. If you don’t want to do the math (and have access to the internet when you need the estimate), here is a site offering an online space capacity calculator (www.eventageous.com) that will help you get a more accurate estimate of a room’s capacity – and it can run calculations for the most common room sets all at once. Tools like this are a great addition to your meeting planning toolkit but, when I really need to know exactly how many people can fit, I work with my Convention Services Manager (CSM) and the hotel’s room specification charts to get actual capacities. Each room is different – you need to take into account the shape, the locations of doors/exits, existence of pillars or other obstacles, and so on. What fits into one space may not in another, even though they have the same square footage! Your CSM will have the experience and knowledge to help you get the most out of the space at his or her property.

As always, the specific needs of your group will have a huge impact on how large of a room you need – but these estimates should at least give you a place to start. One thing to always keep in mind: City Fire Codes are the final arbiter of a room’s maximum capacity. So, just because you could fit more people in based on your calculations doesn’t mean it is legal or safe to do so.

- Karl Baur, CMP

Note: To work it the other direction and figure out how much space you need for a group, you simply multiply the number of people by the per person approximation to get a rough estimate. If I need to serve 300 people in a banquet (which needs approx. 15 square feet per person), then I should be looking for a room that is about 4,500 square feet.

Ed Note: Given the number of people still referencing this post, I have decided to add one more element to it - a downloadable PDF. You can download a one-page PDF "cheat sheet"for looking up various seating capacities based on a room's square footage.