Footprint
The first and most basic thing that you need to take into account is how much space you have at the venue. If you are restricted to a half-acre field, then a 200 foot long tent is probably not going to work very well. You will also be constrained if you need to work around obstacles like water features, hills, or trees. Determining the maximum size of the tent will give you a starting point that you can use to start planning the event.
Event Style
The next thing you should take into consideration is what type of event you will be having and what this will mean for your tent structure size needs. For example, a wedding where you are only anticipating a hundred guests will need a much smaller tent than a trade show where you are expecting a hundred different vendors and displays. Try looking at similar events and figure out what tent size they used.
Interior Configuration
You should also consider exactly what you are hoping to fit inside the tent. Will you need dining tables, or event seating? Do you want a stage? A dance floor? A showcase area? Do you need to include buffet tables or food preparation areas? What types of furniture will you be using, how many of each do you need, and how much space will you need to put between them?
On a related note, you should consider how many people you are hoping to accommodate, as well as what they will be doing. If you need ceremony seating for a few dozen people, you will not need a very large area, but you will need a much bigger tent if you want space for a few hundred people to mix, mingle, and interact. Be sure to consider what kind of crowd management you will need.
Tent Structure Size and Shape
Remember to take into account the shape of the tent you will need. For some events, such as trade shows, a long and narrow rectangle might be an acceptable option, providing lengthy aisles for attendees to wander down. For another event, such as a dance or celebration, a square tent might be more conducive to socializing. You might also want to consider erecting more than one tent if you need food preparation or administrative areas.
Local Requirements
Be sure to consider local laws and requirements. Different states and municipalities might have a variety of different rules when it comes to the right tent structure size; contact your local authorities to ensure that your tent will comply with fire codes and crowd safety regulations.
Cost-Effectiveness
Finally, remember to take your event budget into account. Simply put, larger tents tend to cost more, which puts another constraint on your final tent size. For maximum cost effectiveness, choose a tent that is large enough to fulfill your needs, but is no bigger than it has to be. With these handy tips, choosing perfectly sized temporary structures should be a snap.