How to use the stair stringer calculator
Find the number of steps, the exact riser height and the stringer length for a staircase. Enter total floor-to-floor height, target riser height, tread depth in the fields above; the number of risers, actual riser height, stringer length are computed instantly and plotted on the chart so you can see how the answer changes.
Common searches this calculator answers include “stair calculator”, “stair riser height”, “stair stringer length”, “calculate stair stringer”, “find number of risers”.
Formula
Variables
- H — Total floor-to-floor height (cm)
- rise — Target riser height (cm)
- run — Tread depth (cm)
Worked example
With total floor-to-floor height = 270 cm, target riser height = 18 cm, tread depth = 28 cm, the calculator gives number of risers ≈ 15 steps; actual riser height ≈ 18 cm; stringer length ≈ 499.2995 cm.
Frequently asked questions
What is the stair stringer calculator used for?
Find the number of steps, the exact riser height and the stringer length for a staircase. It helps with questions such as “stair calculator”, “stair riser height”, “stair stringer length”.
What is the formula for the stair stringer calculation?
Number of risers (steps) = ceil(H / rise). Actual riser height (cm) = H / [Number of risers]. Stringer length (cm) = [Number of risers] × √(run × run+[Actual riser height] × [Actual riser height]). Here H is total floor-to-floor height (cm), rise is target riser height (cm), run is tread depth (cm).
What inputs do I need for the stair stringer calculator?
You need total floor-to-floor height in cm, target riser height in cm, tread depth in cm. Each field is pre-filled with a typical example so you can see how the result responds as you edit the numbers.
How do I use the stair stringer calculator?
Type values into the input fields. Results and the chart update instantly. Use Reset to restore the example values, Copy results to paste them elsewhere, or Share to copy a link that preserves your inputs.
Is the stair stringer result exact?
Calculations use standard formulas and double-precision arithmetic, then display about seven significant figures. Real-world measurements carry uncertainty, so treat results as estimates unless your inputs are exact.