The way this is measured is to begin at the leading edge of the stair nosing and run an imaginary vertical line upward until it reaches the top of the railing.
Wall mounted residential stair handrail height code.
Handrail height on the stairs should be no less than 34 inches and no greater than 38 inches.
If they are placed up against a wall they should have a clearance from the wall not less than 1 inches.
All railings built for non individual residential dwellings are built to an installed height of at least 42.
As for guards along a set of stairs that serve as a handrail as well they are allowed to be at a height of no less than 34 inches but no more than 38 inches.
Codes require railings against a wall to be between 30 inches and 38 inches high while handrails on open stairs must be 34 to 38 inches high.
The height is measured vertically from the line connecting the nosing.
Handrail height is the height of the handrail in relation to the stairs.
Railing height measure railing height from the bottom of the ground at each step to the top of where the handrail will be located.
California 2007 building code effective 1 january 2008 for safety guardrails on balconies decks and on the horizontal area of stairway landings for walking areas whose surface is more than 30 inches above adjacent walking surfaces or the ground for group 2 individual residential dwellings as well as for group 3 occupancies specifies that the guardrail must be 42 inches or higher.