Occupancy Load Calculator
Determine the maximum number of people allowed in a space based on International Building Code (IBC) standards.
What is Occupancy Load?
Occupancy load is a building code calculation used to determine the maximum number of people that can safely occupy a specific room or building at one time. This calculation is critical for fire safety, as it dictates the required number of exits, the width of hallways, and the type of fire suppression systems needed.
How to Calculate Occupancy Load
The standard formula used by fire marshals and architects is:
Occupancy Load = Total Floor Area / Load Factor
The "Load Factor" is the amount of square footage assigned per person, which varies depending on how the space is used. For example, a dance floor (highly concentrated) requires much less space per person than a storage warehouse.
Common Load Factors (IBC Standards)
| Function of Space | Sq. Ft. Per Person |
|---|---|
| Assembly (Standing/Chairs Only) | 7 net |
| Assembly (Tables & Chairs) | 15 net |
| Classrooms | 20 net |
| Exercise Rooms | 50 gross |
| Office Buildings | 100 gross |
| Retail (Grade Floor) | 30 gross |
Example Calculation
If you have a restaurant dining room that measures 1,500 square feet and uses tables and chairs (unconcentrated assembly), the calculation would be:
1,500 sq. ft. ÷ 15 (Load Factor) = 100 people.
If that same 1,500 sq. ft. space was used as a standing-room-only concert venue, the calculation would be: 1,500 ÷ 7 = 214 people.
Net vs. Gross Area
Gross Area includes the entire space within the inside perimeter of the exterior walls, including corridors, stairways, and closets. Net Area only includes the actual occupied space, excluding permanent obstructions like thick walls or built-in equipment.