Stair Calculator
The finished floor-to-floor height the stair has to climb.
Number of risers16
Riser heightPass: 6-13/16" · 173 mm
Number of treads15
Tread depthPass: 11" · 279.4 mm
Total run13' 9" · 4.191 m
Stair pitch31.8°
2R + T (comfort)Pass: 24.6" — comfortable
HandrailRequired (4+ risers)
- 16 risers at 6.81" with 15 treads at 11" (riser ≤ 7¾" R311.7.5.1, tread ≥ 10" R311.7.5.2).
- 2R + T = 24.6" is within the comfortable 24–25" range (rule of thumb).
- 4 or more risers — at least one handrail required, 34–38" high (R311.7.8).
- Provide ≥ 6'-8" headroom (R311.7.2) and ≥ 36" stair width (R311.7.1).