Calculate stair handrail length and angle from the rise and run, with optional top and bottom extensions, in feet and inches or metric units.

Height from the bottom rail point to the top rail point (e.g. floor to top nosing).

Level distance between the same two points, not the diagonal.

Top and bottom extensions
Blank means zero. Extra rail length beyond the sloped section.

Related Calculators

Handrail Length Formula

The following formula is used to calculate the handrail length.

HL = √(SL2 + SH2)

Variables:

  • HL is the handrail length (inches)
  • SL is the horizontal run between corresponding rail endpoints (inches)
  • SH is the stair height (inches)

To calculate the handrail length, use the Pythagorean theorem to find the hypotenuse of the right triangle formed by the stair length and the stair height.

What is a Handrail Length?

The straight handrail segment spans the diagonal between corresponding endpoints, with length √(horizontal run² + vertical rise²). Add the actual lengths of selected extensions measured along their paths; projected extension dimensions must first be converted. Returns, fittings, joints, cutting allowances and waste require separate allowance. Length alone does not establish structural support, stability or compliance with building requirements.

How to Calculate Handrail Length?

The following steps outline how to calculate the Handrail Length.

  1. First, measure the horizontal run between the endpoints of the straight sloped rail (SL), not the diagonal stair or rail length.
  2. Next, measure the height of the stairs from the top step to the bottom step (SH).
  3. Use the formula HL = √(SL2 + SH2) to calculate the handrail length (HL).
  4. Finally, use the calculator above to verify the geometry. In inverse modes, enter the straight sloped length excluding extensions. Optional extension fields are actual additional lengths along the rail, not horizontal projections; blank means zero.

Example Problem : 

Use the following variables as an example problem to test your knowledge.

stair length (SL) = 120 inches

stair height (SH) = 72 inches