Staircase Calculator

Calculate staircase dimensions — number of risers, riser height, tread depth, and stringer length from total rise and desired specifications.

🪜 Staircase Calculator

Results

Number of Risers14 risers
Actual Riser Height7.71 in
Number of Treads13 treads
Tread Depth10.5 in
Total Run136.5 in
Stringer Length174.1 in
Stringers Needed2

💡 How to Calculate Staircase Dimensions

Building codes require risers between 4 and 7¾ inches (most common: 7–7¾ inches) and treads with a minimum 10-inch depth. The relationship between riser and tread should satisfy the formula: 2 × Riser + Tread = 24–25 inches for comfortable stairs.

Start by dividing the total rise (floor-to-floor height in inches) by your target riser height (7.5 inches is ideal for comfort). Round to the nearest whole number to get the number of risers. Then divide the total rise by the number of risers to get the exact riser height. The number of treads is always one less than the number of risers.

A 9 ft (108 inch) floor-to-floor rise ÷ 7.5" target = 14.4 → 14 risers. Actual riser = 108 ÷ 14 = 7.71 inches. Treads = 13 × 10.5" = 136.5" (11.4 ft) total run.

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