Handrail Length Calculator
Calculate the handrail length needed for a staircase from the horizontal run and vertical rise.
Supports imperial and metric.
Handrail Length
Handrail Length follows the hypotenuse of the stair angle using the Pythagorean theorem:
Handrail = √(Run² + Rise²)
Where:
- Run = total horizontal distance of stairs
- Rise = total vertical height of stairs
Stair angle: θ = arctan(Rise / Run)
Code requirements (IRC):
- Handrails required when 4+ risers
- Height: 34–38 inches above stair nosing
- Must be graspable (1.25–2 inch diameter)
- Extensions: 12 inches beyond top/bottom
Tip: Add 12–18 inches to the calculated length for top/bottom extensions and fitting waste.
Common stair dimensions:
- Standard rise: 7–7.75 inches per step
- Standard run: 10–11 inches per step