Stringer length
The full length of the inclined load-bearing beam (stringer or string) that the steps rest on. The hypotenuse of the "height–run" triangle.
01 /Stringer length — what it is
The length along the load-bearing element (the stringer or string) is the full length of the inclined supporting beam that the steps are laid on. It is the hypotenuse of a right triangle whose legs are the total rise and the floor run.
Knowing the rise and the floor run, the stringer length is found by the Pythagorean theorem: the square root of the sum of their squares.