Stair Calculator (Risers, Treads, Stringer)
Stair calculator: number of steps, actual riser height, treads, total run, stringer length and angle from the floor-to-floor height.
risers = round(total rise ÷ ideal riser) · 2R + T ≈ 25 in
How to use this calculator
- Type your input in the box.
- The result updates as you type.
- Use “Copy result” or “Copy link” to share it.
Divide the total rise by your ideal riser (about 7–7.75 in), round, and recalculate the exact riser. A comfortable stair satisfies 2 × riser + tread ≈ 24–25 in.
Check local building codes (IRC: max riser 7¾ in, min tread 10 in).
Frequently asked questions
Total rise 108 in, ideal riser 7.5 in, 10 in treads?
14 risers of 7.71 in, 13 treads, 130 in run.
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