Free tool · IBC 2021
Add each space, pick its use and enter its area. You get the occupant load, the exits it needs and the egress width.
| Name | Use | Area (sq ft) | Factor | People | Remove |
|---|---|---|---|---|---|
| 15 net | 160 | ||||
| 5 net | 60 | ||||
| 200 gross | 3 | ||||
| 300 gross | 1 |
Each space is rounded up to whole people, as most plan reviewers do. The code itself doesn’t say how to round.
Draw the plan in Toras and it measures the walking distance from every room to the nearest exit, right on the drawing.
Open your plan in TorasDivide each space’s floor area by the load factor for its use, then add the spaces together (Sections 1004.3 and 1004.5).
A 2,400 sq ft dining room with tables and chairs uses 15 sq ft net per person: 2,400 ÷ 15 = 160 people. Add the bar, kitchen and storage the same way and the restaurant comes to 224.
Gross is everything inside the exterior walls, without taking out corridors, stairs, closets or interior walls. Net is only the area actually used, leaving out corridors, stairs, toilet rooms, mechanical rooms and closets. The table says which one each use takes.
Floor area in square feet per occupant, for every use in the table.
| Use | Sq ft per person | Area |
|---|---|---|
| Accessory storage areas, mechanical equipment room | 300 | gross |
| Agricultural building | 300 | gross |
| Aircraft hangars | 500 | gross |
| Airport terminal, baggage claim | 20 | gross |
| Airport terminal, baggage handling | 300 | gross |
| Airport terminal, concourse | 100 | gross |
| Airport terminal, waiting areas | 15 | gross |
| Assembly, gaming floors (keno, slots, etc.) | 11 | gross |
| Assembly, exhibit gallery and museum | 30 | net |
| Assembly with fixed seats | Seat count | Section 1004.6 |
| Assembly, chairs only (concentrated) | 7 | net |
| Assembly, standing space | 5 | net |
| Assembly, tables and chairs (unconcentrated) | 15 | net |
| Bowling centers | 5 per lane + 7 | net |
| Business areas | 150 | gross |
| Concentrated business use areas | 50 (minimum) | gross, Section 1004.8 |
| Courtrooms, other than fixed seating areas | 40 | net |
| Day care | 35 | net |
| Dormitories | 50 | gross |
| Educational, classroom area | 20 | net |
| Educational, shops and other vocational room areas | 50 | net |
| Exercise rooms | 50 | gross |
| Group H-5 fabrication and manufacturing areas | 200 | gross |
| Industrial areas | 100 | gross |
| Information technology equipment facilities (2024 IBC) | 300 | gross |
| Institutional, inpatient treatment areas | 240 | gross |
| Institutional, outpatient areas | 100 | gross |
| Institutional, sleeping areas | 120 | gross |
| Kitchens, commercial | 200 | gross |
| Library, reading rooms | 50 | net |
| Library, stack area | 100 | gross |
| Locker rooms | 50 | gross |
| Mercantile | 60 | gross |
| Mercantile, storage, stock, shipping areas | 300 | gross |
| Parking garages | 200 | gross |
| Residential | 200 | gross |
| Skating rinks and swimming pools, rink and pool | 50 | gross |
| Skating rinks and swimming pools, decks | 15 | gross |
| Stages and platforms | 15 | net |
| Warehouses | 500 | gross |
| Mall buildings, covered and open | — | Section 402.8.2 |
The 2021 International Building Code, which most US states have adopted. The 2024 edition adds one use, information technology equipment facilities at 300 sq ft gross; it is in the list, marked 2024.
The code doesn’t say. Most plan reviewers round each space up to whole people, so this calculator does too.
Where seats are fixed, the occupant load is the number of seats (Section 1004.6). Pick “Assembly with fixed seats” and enter the seat count. Benches without arms count one person per 18 inches; booths one per 24 inches.
The code gives outdoor areas no fixed factor; the building official assigns one based on how the space will be used (Section 1004.7). Add it as the use you expect, for example tables and chairs.
Only when the building has sprinklers throughout and an emergency voice/alarm system. Sprinklers alone are not enough, and Groups H and I-2 never get the reduction.