Construction Tools
Enter your total rise and target riser height or number of steps. Calculate the number of risers, actual riser height, tread run, total run, and stringer length for your staircase.
Number of Steps
2.00 risers
Stringer length is the diagonal distance from bottom to top, calculated as &sqrt;(rise² + run²).
A staircase consists of risers (vertical steps), treads (horizontal step surfaces), and a stringer (the diagonal support beam). Total rise is the floor-to-floor height. Riser height is the vertical distance between steps (typically 6–8 inches). Tread run (depth) is the horizontal distance of each step (typically 9–11 inches). Total run is the full horizontal distance covered by all steps. Stringer length is the diagonal measurement from bottom to top.
Enter your total rise (floor-to-floor height in inches). Choose whether to set a target riser height or specify the total number of steps. The calculator determines the number of risers, actual riser height per step, total horizontal run, and stringer length. Tread run (depth) defaults to 10 inches but can be adjusted.
Number of risers = ceil(total rise ÷ target riser height). Actual riser height = total rise ÷ number of risers. Total run = (number of risers − 1) × tread run. Stringer length = √(rise² + run²).Start with total rise divided by your target riser height to find how many steps you need. The calculator rounds up and redistributes the height evenly across all risers. Tread run is constant (the depth of each step). Total run is the horizontal distance covered: it's one less than the number of risers because the first riser doesn't need tread space before it. Stringer length uses the Pythagorean theorem: it's the hypotenuse of a right triangle with legs of rise and run.
| Input | Result | Notes |
|---|---|---|
| Total rise = 108 inches, Target riser height = 7 inches, Tread run = 10 inches | 15 risers, Actual riser = 7.20 in, Total run = 140 in, Stringer length ≈ 176.55 in | 108 ÷ 7 ≈ 15.43 → ceil to 15 risers. 108 ÷ 15 = 7.20 in per riser. Run = 14 × 10 = 140 in. Stringer = √(108² + 140²) ≈ 176.55 in. |
| Total rise = 120 inches, Number of steps = 16, Tread run = 10 inches | 16 risers, Actual riser = 7.50 in, Total run = 150 in, Stringer length ≈ 193.39 in | 16 risers with 120 in rise gives 120 ÷ 16 = 7.5 in per riser. Run = 15 × 10 = 150 in. Stringer = √(120² + 150²) ≈ 193.39 in. |
| Total rise = 96 inches, Target riser height = 8 inches, Tread run = 11 inches | 12 risers, Actual riser = 8.00 in, Total run = 121 in, Stringer length ≈ 155.24 in | 96 ÷ 8 = 12 risers exactly. Run = 11 × 11 = 121 in. Stringer = √(96² + 121²) ≈ 155.24 in. |
Riser height is the vertical distance from the top of one step to the top of the next step. Building codes typically limit riser height to 4–8 inches (often 7–7.75 in for residential stairs). Taller risers feel steep; shorter ones are easier to climb.
Tread depth (run) is how far forward each step extends—the horizontal distance of each step surface. Standard tread depth is 10–11 inches (sometimes 12 in for comfort). Stairs with deeper treads feel safer and less steep.
Total run is the full horizontal distance from the start of the first step to the end of the last step. It's calculated as (number of steps − 1) × tread depth. One less because the first riser has no tread before it.
Stringer length is the diagonal distance from the bottom (start of the first step) to the top (end of the last step). It's the length of the support beam (stringer) that holds all the steps. Calculated using the Pythagorean theorem: √(rise² + run²).
Yes. You can enter 7.5 for riser height, 10.25 for tread depth, or any decimal. The calculator handles fractional measurements and displays results to 2 decimal places.
The calculator distributes your total rise evenly across all risers. If your target doesn't divide evenly, actual riser height will be close but slightly different. Adjust your target or step count until the result matches your needs.