ZovaTool

Stair Calculator

# Risers
14
Riser Height
7.714″
Total Run
143″
Stringer
179.2″
Angle
37.1°
2R+T (Blondel)
26.4″
Off comfort range
Building CodePass (IRC)
Handrail length (approx)191.2″

How to use the Stair Calculator

  1. Enter total rise (floor-to-floor in inches).
  2. Enter tread depth.
  3. Set your target riser height (7.5″ is the comfort default).
  4. Read number of risers, exact riser height, stringer length and angle. The Code field flags IRC violations.
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Stairs that feel right

IRC building code: max riser 7¾″, min tread 10″, riser×tread between 75 and 90.

Comfort rule (Blondel): 2R + T ≈ 25″. Our defaults satisfy both.