Quick Calculations
By David Lutz, CMP
If you’ve ever stood in a breakout room with the hotel’s meeting space capacity chart in hand and thought, “There’s no way 125 people can fit in here theater-style,” you know how important it is to be able to independently determine the number of attendees that can be seated comfortably in any given function room. Fortunately, it’s relatively easy to do just that. All you need to do is follow a few simple, step-by-step formulas.
First, you need to calculate how much space you actually have to work with after taking columns and other obstructions into consideration. Here’s how: Measure the room to determine the shortest distances that form the room’s length and width. For example, the hotel may show the dimensions of a room to be 130′ x 60′. But if you factor in the columns along the back wall of the room and the storage areas along the sides of the room, the “clear meeting area” may be significantly less.
Once you’ve determined the clear meeting area, you can use the following formulas to figure out the true capacity of the room for the three most common types of seating – theater-style, classroom-style, and banquet-style. The objective of all three formulas is to ensure that every attendee has an unobstructed view of the screen or speaker, easy access to his or her seat, and sufficient elbow room. Note: To maximize capacity, arrange for the front of the room to be on the narrow wall.
Theater-Style Formula
Most hotels and convention centers offer meeting room chairs that are 20″ front to back and between 17.5″ and 18.5″ wide. The standard used by the majority of facilities is to place the chairs immediately adjacent to each other and to use one chair’s length as a measuring stick between rows. When these standards are used, it’s very difficult to fully utilize the seating area since attendees typically do not want to climb over each other to reach an empty seat or sit shoulder to shoulder with their neighbors if they manage to get a seat. The result? Chairs remain unoccupied.
The following formula adds two to three inches to the above standards, thereby increasing comfort and allowing a greater percentage of the seating area to be utilized.
Step 1: Determine the number of rows that can be accommodated.
Take the clear room length and subtract the space between the screen and the front row (normally two times the screen height) and the space between the back wall and the back row (minimum of four feet). Note: Two times the screen height is a standard that allows a person to view the entire screen comfortably. If you don’t know the screen height, subtract 20 percent from the clear length of the room.
Then divide by the distance between rows, measured from chair back to chair back (3.58 feet or 43 inches).
Round the resulting figure down to the nearest full row.
Note: Do not exceed more than 30 feet of continuous seating before placing aisles. Many city fire codes will dictate a similar standard for adequate ingress and egress. Example: 100 (length of room) – 20 (2 x screen height) – 4 (distance from back wall) = 76 (usable room length)
76 X 3.58 (distance between rows) = 21.2 rows, rounded down to 21 rows
Step 2: Determine the number of chairs that can be set in each row.
Take the clear room width and subtract space for aisles (normally about 15 percent).
Divide by the distance between chairs, measured from chair center to chair center (1.83 feet or 22 inches).
Round the resulting figure down to the nearest chair.
Example: 75 (width of room) – 11.25 lost to aisles (15% of 75) = 63.75 (usable room width) 63.75 X 1.83 (distance between chairs) = 34.84, rounded down to 34 chairs
Step 3: Multiply the number of rows by the number of chairs in each row.
Example: 21 (rows) x 34 (chairs) = 714 people that can be comfortably accommodated in the room
Note: Seats from which the view of the screen or speaker is obscured should be removed. Seats located less than a 30-degree angle to the screen also should be removed since the viewing angle is too acute to provide easy reading of the projected material.
Classroom-Style Formula
Most hotels and convention centers offer six-foot and/or eight-foot tables that are 18 inches wide for their classroom-style setups. To determine the space between rows, the majority of facilities use a six-foot table as a measuring stick. A six-foot table is placed at a 90-degree angle to the first table in the room. The front of the first table is matched up with one end of the six-foot and the back of the second table is matched up with the other end of the six-foot table. The result is a three-foot gap between the two tables [6 feet – (2 x 18 inches)]. This standard is perfect for proper spacing between rows.
The majority of facilities will seat three people at a six-foot table or four people at an eight-foot table (allowing two feet per person). This is also a good standard for most sessions, although you may want to request seating of two people per six foot or three per eight foot if you’re using large binders or conducting computer training.
The following formula uses the above standards, ensuring comfort and allowing for a greater percentage of the seating area to be utilized.
Step 1: Determine the number of rows that can be accommodated.
Take the clear room length and subtract the space between the screen and the front row (two times the screen height) and the space between the back wall and the back row (minimum of four feet).
Divide by the distance allotted per row, measured from table front to table front (4.5 feet or 54 inches, assuming the tables are 18 inches wide).
Round the resulting figure down to the nearest row.
Example: 50 (length of room) – 14 (2 x screen height) – 4 (distance from back wall) = 32 (usable room length)
32 X 4.5 (distance per row) = 7.1 rows, rounded down to 7 rows
Step 2: Determine the number of chairs that can be set in each row.
Take the clear room width and subtract space for aisles (normally about 15 percent).
Divide by the distance allotted per chair, measured from chair center to chair center (2 feet or 24 inches is the minimum space per chair for classroom seating).
Round the resulting figure down to the nearest chair.
Factor in the length of the tables provided by the hotel: six-foot, eight-foot, or both.
Example: 40 (width of room) – 6 (15% of 40 to determine space lost to aisles) = 34 (usable room width)
34 X 2 (distance allotted per chair) = 17 chairs
Since the hotel only has eight-foot tables, you need to determine how many eight-foot tables can fit in the 34 feet available for seating (34 X 8 = 4.25). The number of chairs in each row would be reduced to 16 (4 tables x 4 attendees per table).
Step 3: Multiply the number of rows by the number of chairs in each row.
Example: 7 (rows) x 16 (chairs) = 112 people that can be comfortably accommodated in the room
Banquet-Style Formula
Most hotels or convention centers use round tables that are 60″, 66″, or 72″ in diameter. The standard used by the majority of facilities is to allow five feet between each round, which provides sufficient room for chairs to be placed around the table and for banquet staff to provide meal service. The ideal number of seats per table is eight at a 60″ round, nine at a 66″ round, and 10 at a 72″ round.
To determine how many rounds can fit in a given room, it’s helpful to think of each round as a square. Add five feet to the diameter of the table (60 inches plus 5 feet = 10 feet) and then calculate how many 10-foot squares can be accommodated in the space using the following formula.
Step 1: Determine the number of tables that can be accommodated.
Take the clear room length and divide by each table’s linear feet (from the chart below). Round the resulting figure down to the nearest table.
Take the clear room width and divide by each table’s linear feet. Round the resulting figure down to the nearest table.
Multiply the two numbers.
Example: 75 (length of room) X 10.5 (linear feet for a 66-inch round) = 7.1, rounded down to 7
50 (width of room) X 10.5 (linear feet for a 66-inch round) = 4.76, rounded down to 4
7 x 4 = 28 tables
Step 2: Subtract excess tables that need to be removed for staging, buffets, rear-screen projection, or chairs directly in front of an exit, etc.
Step 3: Multiply the number of tables by the number of chairs to be set at each table (from the chart below).
Example: 28 (number of tables) x 9 (number of people at each table) = 252 people that can be comfortably accommodated in the room
After you’ve taken the time to figure out the capacities of the function rooms, don’t leave the actual setup of the rooms to chance. Be sure to specify, in writing, the standards that you require the hotel to follow such as 4.5 feet between table fronts for a classroom setup or 22 inches from chair center to chair center for a theater-style setup. You may even have to show the setup crew how to properly place the tables and chairs. (Also be sure to clearly communicate what wall you want the chairs to face – north, south, facing airwall, facing banquet service hall.) It’s a little extra work, but it will ensure that your delegates are comfortable. Remember, comfortable delegates are usually attentive delegates.
David Lutz is executive vice president at Conferon, Inc. in Twinsburg, Ohio.
How Many People Can Fit at a Banquet Round?
| Available Sizes | Linear Feet Needed | Number of People |
| 60″ round | 10′ | 6-9 people |
| 66″ round | 10.5′ | 8-10 people |
| 72″ round | 11′ | 9-11 people |
Quick Calculations
To quickly figure out how large of a room you need for a setup, multiply the number of people by the appropriate square footage per person from the formulas below. To determine if a certain meeting room can accommodate a desired setup, divide the room’s total square footage by the appropriate square footage per person from the formulas below.
Theater Style
12 square feet per person for groups of less than 60 people
11 square feet per person for groups of 60 to 300 people (the most common size breakout session)
10 square feet per person for groups of more than 300 people
Classroom Style
22 square feet per person for groups of less than 60 people
20 square feet per person for groups of 60 to 300 people (the most common size breakout session)
17 square feet per person for groups of more than 300 people
Banquet Style
13.5 square feet per person
Conference Style or Hollow Square
30 square feet per person
U-Shape
35 square feet per person
Note:
The smaller the room or more square the room is, the greater the square footage needs per person. In a smaller or square room, there is more wasted space per person in the front, back, and sides of the room