Stair Calculator
Free stair calculator. Enter total rise and target riser height to get the number of risers and treads, riser height, run, stringer length and stair angle for a code-compliant staircase.
About the Stair Calculator
Estimate a straight staircase from total rise, target riser height and tread depth. The calculator rounds the riser count up, then reports the adjusted riser height, tread count, total run, diagonal stringer length and angle. Choose metric or imperial units. It does not check building-code compliance, headroom, landings, handrails or structural strength.
Features
- Riser and tread count from total rise and target riser height
- Exact riser height after balancing the steps
- Total run from tread depth and count
- Stringer length and stair angle for layout
- Works for interior and deck stairs
- 100% client-side and private — instant results, no signup
How to use this tool
The Stair Calculator works right in your browser — no signup, no installation. Follow these steps:
- Select units and enter the measured total rise.
- Enter your target riser height and tread depth.
- Review the resulting step count and dimensions.
- Check the layout against project requirements before using it for construction.
Frequently asked questions
How is the riser count calculated?
Total rise is divided by target riser height and rounded up. The adjusted riser height is total rise divided by that whole-number count; the tread count is one fewer than the riser count.
Does this check building-code compliance?
No. The inputs determine the geometry; the calculator does not validate local code requirements or structural design.
What does stringer length mean here?
It is the diagonal calculated from total rise and total run, before allowances for cuts or connections.
Using the results
The Stair Calculator estimates quantities from your measurements and the stated assumptions. Check dimensions, product coverage and project requirements before buying materials.