This calculator computes required egress width for a door, corridor, or stairway from the occupant load served and the sprinkler status, using the capacity factors in IBC Section 1005 (2021 and 2024 International Building Code). It is a reference estimate, not a code determination: confirm the adopted code edition, occupancy-specific rules, and any local amendments with your local building department.
Before you use this: what this tool is and is not
This is a reference and estimating tool, not a code determination. It applies the capacity factors and minimum-width figures in IBC Section 1005 to the numbers you enter. It does not know your project’s occupancy classification or any local amendment, and it excludes Group H and I-2 occupancies entirely (see below). Confirm the applicable rules with your Authority Having Jurisdiction (AHJ) before you rely on the result.
This page uses IBC Section 1005 as it appears in the 2021 and 2024 International Building Code. Compute stairways per story — not cumulatively down the building — and use the separate "other components" factor for doors, corridors, and ramps.
Calculate required egress width
Egress width calculator
Enter the occupant load served by this component (per story, for a stairway) and its sprinkler status.
This tool does not cover Group H or I-2 occupancies, which have their own separate egress-width rules not included here.
The capacity factors and minimums this tool uses
Per IBC’s means-of-egress sizing provisions under Section 1005 (accessed 2026-09-17):
| Component | Non-sprinklered | Sprinklered (NFPA 13/13R + emergency voice/alarm, excludes Group H and I-2) |
|---|---|---|
| Stairways | 0.3 in per occupant | 0.2 in per occupant |
| Other components (doors, corridors, ramps) | 0.2 in per occupant | 0.15 in per occupant |
Minimum widths: doors need at least 32 in of clear opening. Corridors and stairways are commonly cited as needing at least 44 in, with 36 in permitted where the component serves fewer than 50 occupants — this 36/44 in figure needs one more primary-source check, so confirm it for your specific project. Compute a stairway’s required width separately for each story it serves; do not add occupant loads cumulatively down the building. Doors and corridors always use the "other components" factor, never the stairway factor.
Group H and I-2 occupancies are excluded. They have their own separate egress-width rules, including their own treatment of sprinkler protection, which this tool does not state a figure for and does not compute.
Where Groundbook fits
Groundbook’s document review can compare the corridor, door, and stairway widths shown on your drawings against the code sources you upload for the review, flagging a dimension that appears inconsistent with the requirement it needs to satisfy — the same document-to-code comparison used in Groundbook’s building code compliance review. It does not calculate required egress width for you the way this tool does; use this calculator first, then have Groundbook check the drawn widths against it.