ADA Ramp Calculator

How to Calculate an ADA-Compliant Ramp

ADA (Americans with Disabilities Act) ramp requirements ensure safe, accessible routes for people using wheelchairs, walkers, and other mobility devices. Whether you're building a commercial ramp for code compliance or a residential ramp for aging-in-place, proper slope, width, and landing calculations are critical.

ADA Ramp Requirements

• Maximum slope: 1:12 (one inch of rise per 12 inches of run, or 8.33% grade)
• Minimum clear width: 36 inches between handrails
• Maximum rise per run: 30 inches before a landing is required
• Level landings: Required at top, bottom, and every 30 ft of run. Minimum 60" × 60" at turns.
• Cross slope: Maximum 1:48 (2%)
• Surface: Must be firm, stable, and slip-resistant

Handrail Specifications (ADA/IBC)

• Required: Both sides of ramp when rise exceeds 6 inches
• Height: 34"–38" above ramp surface
• Extensions: 12" minimum beyond top and bottom of ramp run
• Graspable profile: 1.25" to 2" diameter for round handrails
• Edge protection: Required to prevent wheelchairs from rolling off

Slope Ratios Explained

• 1:12 (8.33%): ADA maximum for new construction. Standard for most applications.
• 1:16 (6.25%): More comfortable slope for self-propelling wheelchair users. Recommended when space allows.
• 1:8 (12.5%): Only permitted for existing buildings/spaces where 1:12 is not feasible, and only for max 3" rise.
• 1:20 (5%): Technically not a "ramp" under ADA — classified as a sloped walkway. No handrails required.

Commercial vs Residential Codes

Commercial buildings must comply with ADA Standards for Accessible Design and the International Building Code (IBC). Residential ramps follow IRC requirements, which are generally less stringent. However, if a home receives any federal funding or is multi-family housing, ADA standards apply. Many builders follow ADA standards for residential ramps as best practice.