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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.
Open this calculatorFree, no sign-up required.
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
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.
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.