Stair Landing Calculator
Split a stair into two flights with a landing, straight or with a quarter turn. You get risers per flight, the landing height and the floor space the whole stair takes.
Worked example: edit any value
Two flights and a landing
Risers 21 Treads 19 Lower run 8 ft 9 in Upper run 7 ft 10 1/2 in
How this result was calculated
- Risers for the whole height
R = ⌈160 ÷ 7.75⌉ = 21; h = 7.619 inBoth flights use the same riser height, so the stair feels uniform. - Split into two flights
lower 11 risers (landing at 83.8095 in), upper 10 risersEach flight has risers − 1 treads: the landing is the top step of the lower flight. - Runs
lower 10 × 10.5 = 105 in; upper 9 × 10.5 = 94.5 in - Straight footprint
105 + 36 + 94.5 = 235.5 in
All values (table)
| Item | Value | Note |
|---|---|---|
| Risers (total) | 21 | 11 lower + 10 upper |
| Riser height | ≈ 7 5/8 in | 7.619 in |
| Treads (total) | 19 | Risers − 2 (landing and floor are top steps) |
| Landing height | 6 ft 11 13/16 in | Above the lower floor |
| Landing depth | 36 in | In the direction of travel |
| Lower flight run | 8 ft 9 in | 10 treads |
| Upper flight run | 7 ft 10 1/2 in | 9 treads |
| Footprint | 19 ft 7 1/2 in long | Bottom riser face to top riser face |
When a stair needs a landing
- It is too tall for one flight. The IRC limits a flight to 12 ft 7 in (151 in) of rise between floors or landings (2024 R318.7.3). The IBC limit for other buildings is 12 ft.
- It is too long for the room. An L-shaped stair folds the run into two shorter legs.
- Comfort. A landing gives a resting point and limits how far someone can fall.
The landing must be at least as wide as the stair, and on a straight run at least 36 in deep in the direction of travel (2024 R318.7.6). An L-shaped turn with a square landing the width of the stair satisfies both.
Worked example: a 13 ft 4 in rise
A 160 in rise is over the 151 in single-flight limit. With a 7 3/4 in maximum riser and 10 1/2 in goings:
- 160 ÷ 7.75 = 20.6, so 21 risers of 7.619 in (about 7 5/8 in), all equal.
- Split 11 + 10: the landing sits 83.8 in (about 6 ft 11 13/16 in) above the lower floor.
- Runs: 10 treads × 10.5 = 105 in below the landing, 9 × 10.5 = 94.5 in above it; 19 treads in total.
- Straight with a 36 in landing: 105 + 36 + 94.5 = 235.5 in (19 ft 7 1/2 in) long.
- L-shaped, 36 in wide: an L of 141 in × 130.5 in (11 ft 9 in × 10 ft 10 1/2 in).
Both flights stay under 151 in (83.8 in and 76.2 in). These are automated test fixtures (landing L1).
Choosing where to split
Any split works geometrically if both flights stay within the flight limit and the risers stay equal. Halfway is common. Put the landing where it suits the room: at a window, a doorway, or where an L fits the walls. Use "Risers in the lower flight" under More options to move it. Winders (wedge-shaped treads in the turn) are a different design that this calculator does not model.
Questions people ask
What is the rule for stairs landing?
In the IRC (2024 R318.7.6): a floor or landing at the top and bottom of every flight, at least as wide as the stair, and at least 36 in deep in the direction of travel on a straight run, with limited exceptions (for example at some doors and small exterior stairs). A single flight may rise at most 12 ft 7 in between floors or landings (R318.7.3); taller stairs need an intermediate landing.
What are the OSHA requirements for stair landings?
OSHA rules are for workplaces, not houses. For general industry, landings must be at least as wide as the stair and at least 30 in deep in the direction of travel (29 CFR 1910.25(b)(4)). On construction sites, stairs that are not a permanent part of the structure need landings at least 30 in deep and 22 in wide at every 12 ft or less of vertical rise (29 CFR 1926.1052(a)(1)).
Related tools and guides
- Stair Calculator Risers, treads, total run, angle and a to-scale side view from one height.
- Stair Headroom Calculator Minimum floor-opening length and the headroom an opening gives.
- How many stairs for a height Risers, treads and run for common heights, in one table.
- Stair code requirements Which rulebook covers which stair, with edition-correct section numbers.