Calculate stair stringer details: number of risers, exact riser height, treads, and stringer length.
Stringer Length
— inches
Diagonal of rise and run.Usage Tip
Keep every riser equal; even a small variation between steps is a trip hazard and often a code violation.
THE MATH
risers = round( total rise ÷ target riser )
treads = risers − 1, run = treads × 10
stringer = √(rise² + run²)
treads = risers − 1, run = treads × 10
stringer = √(rise² + run²)
Stairs divide the total floor-to-floor rise into equal risers. The riser count, exact riser height, and stringer length all follow from the total rise and a target step height.
Enter the total rise (floor to floor) and a target riser height (7 to 7.75 inches is typical).
Run assumes a 10 inch tread depth; the stringer length is the diagonal to cut.
Run assumes a 10 inch tread depth; the stringer length is the diagonal to cut.