What Is the ADA Stair Calculator?
Verify full ADA 504/505 compliance for commercial and public stairways. This calculator checks riser height, tread depth, nosing profile, handrail height, width, and extension requirements against the 2010 ADA Standards for Accessible Design.
How to Use This Calculator
- Enter all stair dimensions: rise, tread depth, width, nosing projection.
- Input handrail height and extension length.
- Review the pass/fail compliance check for each ADA requirement.
- Export the compliance report for your permit application.
Why Accurate ADA Stair Calculations Matter
ADA non-compliance in public buildings can result in Department of Justice enforcement actions, private lawsuits, and mandatory retrofits. Stairs in commercial buildings must meet both ADA 504/505 and local building code requirements.
Common ADA Stair Mistakes to Avoid
- Applying residential IRC riser and tread numbers to a commercial stair. ADA 504 sets its own range, 4 to 7 inches for risers and at least 11 inches for tread depth, which is narrower than the IRC's residential allowances.