ADA Ramp Slope Calculator
This ADA ramp slope calculator helps determine if a ramp meets ADA accessibility standards. It calculates the slope ratio and percentage to ensure compliance with the 1:12 maximum slope requirement, helping architects, builders, and property owners create accessible ramps for wheelchair users.
FAQs
What is the maximum ADA ramp slope?
The maximum allowable slope for ADA-compliant ramps is 1:12 (8.33%). This means for every 1 inch of vertical rise, there must be at least 12 inches of horizontal run. This slope ratio ensures safe and accessible passage for wheelchair users and individuals with mobility impairments.
How is ADA ramp slope calculated?
ADA ramp slope is calculated by dividing the vertical rise by the horizontal run, then multiplying by 100 to get a percentage. The formula is: Slope (%) = (Rise ÷ Run) × 100. A compliant slope must be ≤ 8.33%. For example: 6" rise requires 72" run (6/72×100=8.33%).
Are there exceptions to the 1:12 slope rule?
Yes, existing structures with space limitations may allow 1:10 (10%) slopes for 6" maximum rise, and 1:8 (12.5%) for 3" rises. However, new construction must adhere to 1:12 maximum. Always consult local building codes as some jurisdictions may have additional requirements.
Do ADA ramps require handrails?
Handrails are required on both sides for ramps with rise greater than 6 inches or horizontal projection exceeding 72 inches. They must be 34-38 inches high, continuous, and extend beyond ramp runs. Handrails improve safety and accessibility for users with mobility challenges.
What is the maximum length for an ADA ramp?
ADA requires a maximum 30-inch rise per ramp run before requiring a landing. At 1:12 slope, this equals 30 feet of horizontal run. Landings must be at least 60 inches long and as wide as the ramp. Longer ramps require intermediate landings every 30 feet.