About this tool
Compute step count, exact riser height, and total run for a stairway from total rise. Targets a 7.5″ riser by default — typical residential code.
Formula
N = round(totalRise / targetRiser). actualRiser = totalRise / N. totalRun = (N − 1) × treadDepth.
Worked example
108″ rise, 7.5″ target → 14 steps, 7.71″ each, 13 treads × 11″ = 143″ run.
Notes
Most US codes: max 7.75″ riser, min 10″ tread. The "2·R + T ≈ 25″" rule is an old comfort heuristic. Always check local building code.