About the Stair Stringer Calculator
Stringer length, board size and cutting layout for a set of stairs.
Also known as: stringer length calculator, stair carriage, cut stringer layout, stair board size.
How to use this calculator
- Enter number of risers, rise per step, going per step, stair width and the other fields.
- The result updates instantly as you type — press Calculate (or Enter) at any time.
- Review the breakdown shown under the main result.
- Use Copy result or Share to save the answer or send a link with your inputs.
Formula
stringer = √(total rise² + total run²)
Worked example
Using the values pre-filled in the calculator above:
- Number of risers = 14
- Rise per step = 190 mm
- Going per step = 250 mm
- Stair width = 900 mm
- Stringer thickness = 38 mm
the calculator returns:
- Stringer length: 4,199.8 mm
- In metres: 4.1998
- Total rise: 2,660 mm
- Total run: 3,250 mm