What Is the Nosing Calculator?
Calculate stair nosing projection, overhang depth, and verify compliance with IRC and ADA nosing requirements. Stair nosings - the front edge of each tread that overhangs the riser - play a critical role in both safety and effective tread depth.
How to Use This Calculator
- Enter the actual tread depth and desired nosing projection.
- Review the effective tread depth (actual + nosing).
- Check compliance with IRC maximum nosing projection (1¼ inches).
- Verify nosing radius and uniformity requirements.
Why Accurate Nosing Calculations Matter
Nosing projection affects the effective tread depth - the usable stepping surface. The IRC limits nosing projection to ¾ inch to 1¼ inches and requires uniform nosing across all treads. Excessive or non-uniform nosing is a tripping hazard.
Building Code References
Related Tools
Frequently Asked Questions
What is the maximum nosing projection?+
The IRC allows nosing projection between ¾ inch and 1¼ inches. ADA standards require a maximum ½-inch nosing radius with no abrupt undersides.