California Building Code Occupancy Load Table 1004.5

To calculate how many people a space can legally hold under the California Building Code occupancy load table, divide the floor area by the occupant load factor listed in Table 1004.5, using gross or net area exactly as the table specifies for that use, and round up to the next whole person. That number, called the occupant load, then drives how many exits the space needs, how wide corridors and doors must be, and which direction doors swing. The current requirements sit in Chapter 10 of the 2025 California Building Code (Title 24, Part 2), effective January 1, 2026.

The Formula and How Rounding Works

For any space without fixed seating, the occupant load equals floor area divided by the occupant load factor in Table 1004.5. The code says the load “shall be not less than” the result, so you always round up. A 3,200-square-foot office divided by 150 gives 21.3, which becomes an occupant load of 22.

Run the calculation separately for each distinct functional area. One floor may contain a classroom, a storage closet, and a corridor, each with its own factor. Add the individual loads together to get the total for the story or the building, and that total is what egress design has to accommodate.

Gross Floor Area vs. Net Floor Area

Table 1004.5 tells you which measurement to use for each space type, and the choice is not interchangeable. Gross area for the same room can run 15 to 25 percent larger than net area, so mixing them up throws every downstream number off.

Gross floor area is everything inside the exterior walls: interior partitions, restrooms, mechanical closets, structural columns, all of it. You measure wall to wall and subtract nothing. Net floor area is only the space actually available to occupants; you subtract walls, columns, fixed equipment, restrooms, closets, and mechanical areas.

The table marks “gross” or “net” next to each factor. Business areas use gross. Assembly spaces with chairs use net. Applying net area where the table calls for gross overcounts occupants and can force you to add exits or widen corridors you don’t actually need. Applying gross where the table calls for net undercounts occupants and creates a real safety problem.

Common Factors From Table 1004.5

The occupant load factor is the square footage allotted to each person. A lower factor means a denser space; a higher factor means people are spread out. California adopts the IBC table with state amendments.

Assembly Spaces

Assembly has the widest spread because activity density varies so much:

Standing space: 5 net square feet per person
Concentrated seating (chairs only, not fixed): 7 net square feet per person
Unconcentrated (tables and chairs): 15 net square feet per person
Gaming floors: 11 gross square feet per person
Exhibit galleries and museums: 30 net square feet per person
Stages and platforms: 15 net square feet per person

A 2,000-square-foot banquet hall set with tables and chairs works out to 134 occupants (2,000 ÷ 15 = 133.3, rounded up). Rearrange the same room for a standing reception and the load jumps to 400.¹

Business, Educational, and Industrial Spaces

Business areas (offices): 150 gross square feet per person
Educational classrooms: 20 net square feet per person
Vocational shops: 50 net square feet per person
Industrial areas: 100 gross square feet per person
Day care: 35 net square feet per person

Classrooms pack more people into less space than offices, which is why the factor is so much lower. A 600-square-foot classroom counts as 30 occupants; the same 600 square feet as office space counts as 4.¹

Mercantile, Residential, and Storage Spaces

Mercantile (retail sales floors): 60 gross square feet per person
Residential: 200 gross square feet per person
Dormitories: 50 gross square feet per person
Commercial kitchens: 200 gross square feet per person
Storage, stock, and shipping: 300 gross square feet per person
Accessory storage and mechanical equipment rooms: 300 gross square feet per person
Warehouses: 500 gross square feet per person

Warehouses and mechanical rooms sit at the high end because very few people occupy those spaces relative to their size. A 15,000-square-foot warehouse produces an occupant load of only 30.¹

Fixed Seating and Mixed-Use Spaces

The table formula doesn’t apply where seating is fixed. Theaters, auditoriums, lecture halls, and stadiums are calculated by counting the actual installed seats. Continuous seating without dividing arms (pews, bleachers) counts as one person per 18 inches of seating length. Restaurant booths use one person per 24 inches of booth length.

Many buildings mix uses on a single floor, and that is where load calculations most often go wrong. A restaurant with a fixed-booth section and an open dining area needs two calculations: count the booth occupants by seating length, divide the open dining area by 15 net square feet per person, and add the two together. Overlooking a secondary use area near the entrance, like a lobby or waiting zone, is one of the most common errors.

Increasing the Load Beyond the Table

The number produced by Table 1004.5 is a floor, not a ceiling. You can operate a space at a higher occupant load if every other code requirement (exits, fire protection, plumbing fixtures) is sized for the higher number, and if the load never exceeds one person per 7 square feet of occupiable floor space. The fire code official can require a seating or equipment diagram to confirm the layout supports the increase.²

This provision comes up with event venues and restaurants that reconfigure for different functions. A banquet hall designed for 200 seated guests might host a standing cocktail event for 350, but only if the exits, corridor widths, and fire suppression can handle 350. Removing the tables is not enough; every downstream egress requirement has to be revisited.

What the Occupant Load Controls

Once you have the number, it feeds three egress requirements.

Number of Exits

Most spaces with an occupant load above 49 need at least two exits. Below that threshold, certain occupancies (business, educational, and mercantile among them) can function with a single exit if travel distance limits are met. At the story level, the minimums scale with total load: two exits for up to 500 occupants, three for 501 to 1,000, and four for anything above 1,000.

Exit Width

Required width of each egress component is the occupant load it serves multiplied by a capacity factor. For corridors, doorways, ramps, and other non-stairway components, the factor is 0.2 inches per occupant. For stairways it is 0.3 inches per occupant, reflecting slower movement on stairs. Both factors can be reduced in buildings equipped throughout with automatic sprinklers and an emergency voice/alarm system.³

A corridor serving 200 occupants needs at least 40 inches of clear width (200 × 0.2). A stairway serving the same 200 needs 60 inches (200 × 0.3). The code also sets absolute minimum widths for corridors and stairways that may control when the occupant load is low.

Door Swing

Doors serving a room with an occupant load of 50 or more must swing in the direction of exit travel, which usually means outward. This keeps a crowd from pressing a door shut and trapping people behind it. Rooms below 50 are generally allowed inward-swinging doors, though high-hazard occupancies always require outward swing regardless of load.⁴

Posting the Load and Overcrowding

Assembly occupancies are generally required to post a sign near the main exit showing the maximum occupant load approved by the fire code official. The California Fire Code defines overcrowding as exceeding the posted or authorized capacity, or allowing people to sit or stand in locations that block aisles, corridors, stairways, or exits. Both are prohibited, and the fire code official can enforce compliance.⁵

Enforcement ranges from a written notice to an order to immediately reduce occupants or vacate the building. Owners and event managers are responsible for monitoring actual attendance against the posted capacity, especially in venues with fluctuating turnout like bars, nightclubs, and banquet halls. The occupancy load calculation is the number you are legally accountable for every time the doors open.⁶

1
ICC Digital Codes. 2024 International Building Code – Chapter 10 Means of Egress
2
UpCodes. California Fire Code 2025 – Chapter 10 Means of Egress
3
ICC Digital Codes. 2021 International Building Code – Chapter 10 Means of Egress
4
UpCodes. California Building Code 2022 – Chapter 10 Means of Egress
5
UpCodes. Overcrowding, 24-Hour Care
6
Cornell Law Institute. California Code of Regulations Title 19 3.27 – Overcrowding