Stair Calculator
Explore stair risers, treads, run, angle, and stringer geometry.
Preparing your calculator…
How this calculator works
Risers = ceiling(total rise ÷ desired maximum riser height), with at least two risers. Actual riser = total rise ÷ risers. Treads = risers − 1, assuming the upper floor acts as the landing. Run = treads × selected tread depth. Angle uses atan2(rise, run); geometric stringer length uses the Pythagorean theorem.
Use current quotes, local rates, and measured dimensions to make this estimate useful for your situation.
Frequently asked questions
Why is there one fewer tread than risers?+
The upper landing or floor serves as the final stepping surface. Different layouts need their own landing allowance.
Does this verify building code?+
No. Building-code limits vary by jurisdiction, and structural/stringer cuts affect strength. Verify the full design locally before building.