Where to put the landing
Put the landing on a riser line: its height must be a whole number of risers above the floor, or the steps will not match. The calculator splits the riser count in half by default; under More options you can move the landing up or down to suit a window, a door or the room below.
The riser height comes from the whole stair, so first work out the straight version in the stair calculator. Every riser above and below the landing must be the same within 3/8 in under the IRC[1].
Landing size rules by code
A landing must be at least as wide as the stair, and the IRC also wants it at least 36 in deep in the direction of travel[1].
| Code | Landing size | When one is needed |
|---|---|---|
| US IRC[1][2] | width ≥ stair width; depth ≥ 36 in (914 mm) | top and bottom of each stair; a flight may rise at most 151 in between landings |
| England[3] | as wide and as long as the narrowest part of the flight | top and bottom of every flight |
| Canada[4] | as wide and as long as the stair width (a straight landing need not exceed 1,100 mm) | top and bottom of each flight; max 3.7 m per flight |
| Australia[5] | at least 750 mm long (500 mm from the inside edge at a turn) | flights of at most 18 risers |
The 2024 IRC renumbered the landing section to R318.7.6 and added exceptions, such as no top landing for an exterior stair of two or fewer risers at a door[2].
L-shaped stairs, U-shaped stairs and straight runs
L-shaped stairs turn 90° at the landing, U-shaped stairs turn 180°, and a straight stair runs on past the landing; this stair calculator with landing gives the footprint of each:
- L-shaped (quarter turn): the lower flight's run plus the landing square on one wall, and the upper flight's run plus the landing on the other.
- U-shaped (half turn): the longer flight plus the landing depth in length, two stair widths across.
- Straight with a mid landing: both runs plus the landing depth in one line. It is the longest footprint but the easiest to frame.
Winders can replace a flat landing at a turn, but they bring their own rules: under the IRC each winder needs 10 in of tread at the walkline, 12 in in from the narrow side, and at least 6 in at its narrowest[1].
Framing the landing
A landing is a small floor: joists at the landing height minus the floor thickness, sheathing and the finish surface. The upper flight's stringers bear on the landing framing; the lower flight's stringers hang from its rim. Size the joists like any floor with the joist span calculator, and cut each flight's stringers with the stair stringer calculator.
Frequently asked questions
How big does a stair landing have to be?
Under the IRC, at least as wide as the stair and 36 in deep in the direction of travel. A 36 in wide stair needs at least a 36 × 36 in landing.
When is a landing required on stairs?
The IRC limits one flight to 151 in (12 ft 7 in) of rise, so taller stairs need an intermediate landing. Landings are also required at the top and bottom of each stair, with some exceptions.
How do I calculate the landing height?
Multiply the riser height by the number of risers below the landing. With 7-5/8 in risers, a landing after 8 risers is 61 in above the floor.
What are L-shaped stairs?
Two flights joined by a square landing that turns the stair 90°. Each flight follows its own wall.
Do L-shaped stairs save space?
They save length, not area: the run is folded around a corner, so the stair fits a shorter wall at the cost of a landing square.
Sources
- 2021 International Residential Code, Chapter 3: Building Planning (R301.5, R311.7 stairways, R312 guards)
- 2024 International Residential Code, Chapter 3 (R318.7 stairways, R320 handrails, R321 guards)
- Approved Document K: Protection from falling, collision and impact (2013 edition, for use in England)
- National Building Code of Canada 2020, Division B, Part 9, Section 9.8 Stairs, ramps, handrails and guards
- ABCB Housing Provisions, Part 11.2 Stairway and ramp construction (NCC 2022)