L-Shaped Steel Stair Calculator with Landing

Opening

Y
in
X
in
W
in

Steps

Z
in
F
in

Flights & turns

P
Q

Structure

A
in
G
in
B
in
H
in
D
in
U
°
T

Options

Finishes

Structure

Anthracite RAL 7016

Treads

Natural oak

Loading the 3D view…L-Shaped Steel Stair Calculator with Landing

StairGen Pro › L-Shaped Steel Stair Calculator with Landing

Guide & codes

This L-shaped steel stair calculator handles two flights of bracketed stringer meeting at a square landing, a quarter turn of 90°. It is the usual steel stair with a landing when the opening is too short for a straight flight: the first flight runs along a wall, the landing turns the corner and the second flight arrives at the upper floor.

You set the total rise (Y), the run of the upper flight including the landing (X), the width (W) and how many steps go before (P) and after (Q) the turn. The calculator places the landing, splits the rise and produces the stringers, landing frame, corner post and railing with their marks. If you are searching for a DWG of an L-shaped steel staircase, the DXF generated from your dimensions opens straight in AutoCAD, with the steel staircase design dimensions already on it.

When to choose this stair

The L-shaped steel stair with a landing is the answer when the opening is too short for a straight run but has two free sides: the first flight climbs along one wall and the second leaves the landing at 90°. The square landing, 1,000 × 1,000 mm with the default values, gives a place to stop halfway and makes it easier to carry furniture up.

Compared with a turn made of winders, the landing takes more floor area, but every tread keeps the same going across its width, which is the safest option. Compared with the sawtooth version, the stringers here are straight, with a bracket per tread. With P = 7 steps below and Q = 8 above, moving a step from one flight to the other keeps the riser, changes the landing height and changes the going of the upper flight.

Calculator parameters

Each dimension carries the letter used in the editor and on the drawings.

YTotal rise
default 2,800 mm · 500 to 8,000 mm
Height from the lower floor to the finished upper floor.
XTotal run
default 3,250 mm · 500 to 12,000 mm
Plan length available for the flight (on turning stairs, the upper flight).
WStair width
default 1,000 mm · 500 to 2,500 mm
Clear width of the flight.
ZTread thickness
default 50 mm · 3 to 120 mm
Thickness of the tread (board or plate).
FNosing
default 50 mm · 0 to 100 mm
How far each tread overhangs the one below.
PSteps, lower flight
default 7 · 1 to 25
Steps before the turn.
QSteps, upper flight
default 8 · 2 to 25
Steps after the turn, up to the top.
AStringer depth
default 100 mm · 30 to 300 mm
Depth of the stringer tube.
GStringer width
default 50 mm · 20 to 300 mm
Width of the stringer tube.
BBracket size
default 100 mm · 20 to 200 mm
Tube section of the bracket under each tread.
HHeight over stringer
default 60 mm · 0 to 400 mm
Vertical gap between the stringer and the tread.
DBracket overhang
default 60 mm · 0 to 300 mm
How far the tread projects beyond the bracket in the walking direction.
UBracket angle
default 10° · -30 to 45°
Tilt of the bracket from vertical.
TNumber of stringers
default 1 · 1 to 3
One centre stringer, two side stringers or three.

How it's calculated

The total rise Y = 2,800 mm is shared between 16 risers, counting the step up onto the landing: 175.0 mm each. On the upper flight, the length X = 3,250 mm minus the landing width leaves room for Q = 8 steps, with a run of 281 mm and a tread depth of 331 mm including nosing.

The step formula comes to 2 × 175.0 + 281 = 631 mm and the pitch to 31.9°: “Comfortable stair”. The most effective way to fine-tune comfort is usually to move steps between the two flights (P and Q) or add one; the Summary panel says how many and applies it.

The landing is a square with sides equal to the stair width W = 1,000 mm, built from a tube frame with a post at the free corner. The Reverse turn direction switch makes the stair left-hand or right-hand without changing any dimension.

Result with the default values

Comfort verdict: Comfortable stair.

Complies with IRC / IBC

Step formula 2R + G631 mm600 – 660 mm
Tread depth331 mm≥ 280 mm
Pitch31.9°30° – 40°
Riser175 mm≤ 197 mm
Going281 mm≥ 254 mm
Clear width1,000 mm≥ 914 mm
Guarding height900 mm≥ 864 mm

Steps

Risers16 pcs
Riser height175 mm
Run (going)281 mm
Tread depth (run + nosing)331 mm
Open riser gap125 mm
Pitch31.9°
Nosing-to-nosing distance331 mm

Structure

Tread area4.969 m²
Bracket spacing on stringer331 mm

Building codes

In the US, the IRC requires a landing at least as wide as the stair it serves and limits a single flight to 151 in (3835 mm) of rise between landings. Approved Document K in England asks for landings at least as wide and as long as the narrowest flight width, clear of door swings. Australia's NCC allows 2 to 18 risers per flight. The strength of the stringers, landing frame and post is a matter for the structural design.

The calculator checks comfort (2R + G, going and pitch) and the building code of the country you pick in the panel (here, IRC / IBC for a dwelling): only the limits that code sets for riser, going, 2R + G, width, pitch, risers per flight and guarding. It is for guidance only: always confirm the code in force and local rules.

Building codes by country, with sources

Parts with the default values

The DXF (AutoCAD 2007, in millimetres or inches) carries these parts with their shop marks: one dimensioned sheet per part, the general arrangement and the bill of materials with weights.

What's in the DXF
  • Z1StringerTube 100×50 × 1
  • Z2StringerTube 100×50 × 1
  • S1BracketTube 100×100 × 1
  • S2BracketTube 100×100 × 14
  • E1Treadt=50 × 15
  • M1Landing frameTube 100×50 × 2
  • M2Landing frameTube 100×50 × 2
  • R1Landingt=50 × 1
  • P1PostTube 80×80 × 1
  • B1HandrailTube Ø42.4 × 1
  • B2BalusterRound bar Ø16 × 15
  • B3HandrailTube Ø42.4 × 1

Frequently asked questions

How do you calculate steel stairs with a landing?

The landing counts as one more step: divide the total rise by all the risers, including the one up onto the landing, and divide each flight's run by its treads. Then check 2R + G. The calculator does both at once and lets you move steps from one flight to the other.

How big is the landing of an L-shaped stair?

Here it is a square as wide as the stair (1,000 mm with the default values), which is the minimum that keeps the full width through the turn under the IRC and Approved Document K.

Can it have sawtooth stringers?

Yes: the L-shaped sawtooth steel stair calculator uses the same step layout with zig-zag stringers instead of brackets.

What about the same stair in wood?

The L-shaped stair calculator for wood uses board stringers and timber beams for the landing, with the same calculation rules.