Home / Tools / Egress Stairway (IBC) H · Life Safety

Egress Stairway Geometry — IBC §1011 (2021)

Number and height of risers, treads, flights and intermediate landings for a story height, with the §1011 limits on riser, tread, flight rise, width and headroom.

Stair

Floor-to-floor rise in

Clear width in

Tread depth in

Occupant load served (optional)

Headroom (optional) in

Stair within a dwelling unit of Group R-2 or R-3 (§1011.5.2 exception)

Results

Risers × height · treads × depth—

Flights · intermediate landings × depth—

Horizontal run (treads + landings)—

§1011 compliance—

§	Item	Limit	OK

IBC 2021§1011.2, 1011.3, 1011.5.2, 1011.6, 1011.8 — as reproduced in state-adopted texts (California CBC/CFC §1011) and consistent secondary sources. Section numbers were 1009 before the 2015 IBC. The IRC (one- and two-family dwellings) is a separate code with 7¾ in risers and 10 in treads.

VerifiedPublished examples reproduced: 108 in → 16 risers of 6.75 in; 119 in → 17 risers, 16 treads, 176 in of run.

Preliminary calculation tool. Final design requires the full text of the referenced standard (see the sources on this page) and review by a licensed PE.