What Is the Skirt Board Calculator?
Calculate skirt board length, angle cuts, and material requirements. Skirt boards (also called skirting or stair trim) are the finish boards installed against the wall along a staircase. They cover the gap between the stair components and the drywall, providing a clean finished appearance.
How to Use This Calculator
- Enter total rise, total run, and the desired skirt board width.
- Review the calculated board length (hypotenuse), cut angle, and material needed.
- Use the angle for miter cuts on your miter saw or circular saw.
Why Accurate Skirt Board Calculations Matter
Skirt boards run diagonally along the wall at the stair angle. The length is the hypotenuse of the rise-and-run triangle, plus extra length at top and bottom for transitions. Accurate angle calculation ensures tight joints at the top and bottom landings.
Common Skirt Board Mistakes to Avoid
- Cutting the skirt board to the stringer length alone, without adding extra material for the transition cuts at the top landing and bottom floor.
- Using the wrong angle on the miter saw. The skirt board's cut angle matches the stair's pitch, not a generic 45-degree miter, so it has to be calculated per project.