Stair Geometry Calculator
Enter total rise, target rise and tread to calculate steps, total run and angle; optionally check DIN 18065.
From total rise to riser count
Total rise is divided by target riser height, rounded to a whole count, and redistributed evenly.
Tread, run, and angle
Tread is horizontal depth. Run and angle follow from tread and actual rise.
Example with 280 cm
An 18 cm target gives 16 risers at 17.5 cm. A 28 cm tread across 15 treads produces a 420 cm run.
What is missing before construction
Landings, headroom, structure, guards, and local rules are not designed. The optional check is not approval.
Frequently Asked Questions
How does the calculator determine the number of risers?
It divides total rise by the target riser height, rounds to a whole count, and then recalculates one equal actual riser height.
What do rise and tread mean?
Rise is the vertical height between adjacent tread surfaces. Tread is the usable horizontal depth of one step.
How does the step formula work?
It compares twice the riser height plus one tread depth as a comfort indicator. The optional DIN output is only a simplified preliminary check, not approval.
Why must the riser count be rounded?
A staircase cannot contain a fractional riser. After rounding, the calculator distributes total rise evenly across the whole riser count.
Are landings and headroom included?
No. The model covers a simple straight flight. Landings, floor openings, headroom, guards, and structure are excluded.
Why does this not replace construction planning?
Site measurements, structure, use, tolerances, and local rules require qualified review. The result describes only the entered geometry.