It is important to get the correct size of marquee to suit the wedding reception. A fine balance must be struck between having enough room for comfort and so much space that the marquee lacks atmosphere.
The marquee supplier should work out the size required, based on the couple's ideas and the number of guests. They will draw up a proposed floor plan.
Don't forget that there may also be a bar area and a dance floor; it's safe to assume that a third to half of the wedding guests will be dancing at any one time. Remember to allow room for extras such as the cake table, table for wedding presents and so on.
Be careful not to underestimate the amount of standing room required, as the waiting staff will need space to circulate when serving drinks