How this calculator works
It divides your total floor-to-floor rise by a comfortable target riser height to get a whole number of steps, then recalculates the exact riser height and the total horizontal run.
Worked example — a 108 inch total rise:
108 ÷ 7.5 ≈ 14 steps → riser height 7.71 in, 13 treads, 130 in of run.
108 ÷ 7.5 ≈ 14 steps → riser height 7.71 in, 13 treads, 130 in of run.
Keep every riser equal
Building codes require all risers within a staircase to be nearly identical (within 3/8 inch) — uneven steps are a trip hazard. That’s why we round to whole steps and recompute.
Frequently asked questions
What is a comfortable stair riser height?
About 7 to 7.75 inches; most codes cap risers at 7.75 in.
How do I calculate number of stairs?
Divide the total floor-to-floor height by your target riser height and round to a whole number.