Stair calculator

How it works

The number of risers is the total rise divided by the target riser height, rounded. Tread depth follows Blondel’s rule (2 × riser + tread ≈ 25 in), which matches a natural stride.

How to measure

Measure from the finished floor below to the finished floor above, including flooring thickness.

Tips

• All risers must be equal; a single odd step is a trip hazard.
• Keep at least 6 ft 8 in of headroom.
• Check local code for handrails and minimum width.