Stair Stringer Calculator
Calculate the diagonal stringer length and angle for a staircase from its total rise and run.
- Free to use
- Accurate results
- No registration required
- Works on all devices
Enter the total rise and run of your staircase to find the diagonal stringer length and angle.
Your result
5
Stringer length
Stringer angle36.87
AI explanation
Formula
Stringer length = √(rise² + run²) (Pythagorean theorem); angle = arctan(rise ÷ run)Worked example
3m rise, 4m run
| Field | Value |
|---|---|
| Total rise (m) | 3 |
| Total run (m) | 4 |
| Stringer length | 5 |
| Stringer angle | 36.87 |
Assumptions
- Gives the raw diagonal length only — actual stringer boards need extra material at each end for the top and bottom step cuts, not included here.
Frequently asked questions
What is a stair stringer?
The stringer is the diagonal structural board (or pair of boards) that supports the individual steps of a staircase, running from the bottom to the top of the stairs.
Does this length include the cuts for individual steps?
No — this is the raw diagonal length between the top and bottom points. Actual stringer lumber needs extra length beyond this for the step notches and end connections.
How do I find the number of steps for this staircase?
Use the Stair Calculator, which computes the number of steps and riser height from the total rise and your desired riser.