Calculate step count, riser height, tread depth and stringer length.
Formula: Risers = ceil(total rise ÷ desired riser). Riser height = total rise ÷ risers. Tread depth = total run ÷ (risers − 1). Stringer length = √(rise² + run²).
Related: Try our deck calculator, lumber calculator, or flooring calculator for your project.
| Parameter | Requirement |
|---|---|
| Max riser height | 7.75 inches |
| Min tread depth | 10 inches |
| Min stair width | 36 inches |
| Max riser variation | 3/8 inch |
| 2R + T comfort range | 24-25 inches |
Tip: Always check local building codes. Some areas have stricter requirements. Cut stringers from 2×12 lumber, minimum 3 stringers for 36-inch stairs.