In calculating the space required, you'll need to consider the number of guests, the type of event, method of seating, and what activities are planned. Events with entertainment may also need a stage, dance floor, and dressing rooms. Visit the site in person, and draw a rough diagram of the room. Does the site have tables and chairs already set up? If so, ask the director what the seating capacity is. However, don't rely on their figure alone: Measure the room dimensions to get the total square footage. Remember that pillars and other features cut down on the usable space. If you'll be bringing in tables, determine their size, how many they seat, and how many such tables will fit. Allow room for chairs to pull out, and waiters to circulate easily. On average, you need 8 to 10 square feet per person for a stand-up buffet; sit-down banquets require 10 to 14 square feet per guest. When holding an exhibit, figure about 225 square feet for each 10 by 10 booth; this includes space for aisles. If an annual event starts outgrowing its location, look for a larger site; but don't choose a room that dwarfs the size of the crowd.