Quarter-turn stair calculator for L-shaped layouts
Use a quarter-turn layout when a straight flight does not fit or when the room benefits from a 90-degree change in direction. Enter the length of each flight, choose left or right, and compare the resulting geometry live.
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Best for
- • Corners and L-shaped stairwells
- • Breaking up a long climb with a landing
- • Comparing left- and right-turn arrangements
Measurements to take
- • Finished floor-to-floor height
- • Lower and upper flight lengths
- • Flight width
- • Left or right turn
- • Opening length and floor thickness
Results you get
- • Steps in each flight
- • Riser height and going by flight
- • Pitch and Blondel values
- • Estimated minimum headroom
- • Landing and parts schedule
Example with numbers
Worked example: a quarter-turn layout
For a 2,800 mm climb, 16 equal risers can be split around a 900 mm landing. StairEditor then checks each flight against the space available.
Starting measurements
- • Floor-to-floor height: 2,800 mm
- • Two 900 mm-wide flights
- • Landing: 900 × 900 mm
Starting result
- • 16 risers at 175 mm
- • Target going: 270 mm
- • Blondel value: 620 mm
- • Pitch: about 33°
Illustrative example only: verify the opening, headroom, structure, and applicable rules before building.
What to have reviewed
The current quarter-turn export is a design summary packet. Use it to review the layout and measurements with a builder; it is not a complete fabrication drawing for landing structure, stringer joinery, or guarding.
Guides for this calculation
Take the right measurements and check what limits the plan before you finalize your stair.
Layouts
Straight vs quarter-turn stairs: choosing a layout
Straight or quarter-turn stairs? Compare footprint, landings, comfort and circulation to pick the layout that fits a compact room or a corner.
Planning
Stair headroom: what to check before building
How stair headroom depends on the floor opening, slab thickness and finishes, and the layout mistakes that cause clearance problems near the top of a flight.
Renovation
Stair measurements to take before a renovation
The room, opening and floor measurements to collect before redesigning a staircase, from finished heights to obstructions and slab thickness.
Common questions
Can the stair turn left or right?
Yes. Switch the turn direction in the editor and the top and isometric views update immediately.
Does this version use winders?
The current quarter-turn model uses a landing between two flights. Winder-step geometry is not part of this calculator.