Check riser and tread against ADA 504 requirements (riser 4-7 inches, tread minimum 11 inches).
ADA 504 requires uniform risers between 4 and 7 inches and treads of at least 11 inches, with specific nosing and handrail provisions. This checks the core riser and tread numbers.
ADA 504 requires uniform riser heights of 4 to 7 inches, tread depths of at least 11 inches, specific nosing profiles, and handrails on both sides.
Yes, 7 inches is the maximum allowed riser under ADA 504. Risers must be uniform within the flight.
Yes, ADA 505 requires handrails on both sides of stairs, with extensions at the top and bottom.
Stairs on an accessible route in covered facilities follow tighter rules than a typical residential stair. Risers and treads must be uniform, open risers are not permitted, and the tread surface must be slip-resistant. Handrails are required on both sides, mounted at a consistent height, and must extend horizontally beyond the top and bottom risers so a user has something to hold before and after the steps.
This calculator sizes the flight to those expectations — uniform risers across the total rise, a compliant tread depth, and the handrail extensions — so the result reflects accessible-egress practice rather than the looser residential minimums. Always confirm the specific figures against the ADA Standards and the building code edition your jurisdiction enforces, since accessible-route requirements carry legal weight.