ADA Ramp Slope Calculator
Ensure your wheelchair ramp meets the Americans with Disabilities Act (ADA) standard 1:12 slope ratio.
Measure the height from the ground to the top of the threshold.
Recommended Specifications:
Ramp Length (Run)
0 Feet
Mandatory Landings
0
Note: ADA standards require a landing for every 30 inches of vertical rise. Additional length for landings (minimum 5'x5′) is required.
Slope Ratio: 1:12 (ADA Standard)
Total Horizontal Run: 0 Inches
How to Calculate ADA Ramp Length
Building an accessible entrance requires precision to ensure safety and compliance. The Americans with Disabilities Act (ADA) provides specific guidelines for commercial and public ramps to ensure they are not too steep for wheelchair users to navigate independently.
The 1:12 Slope Ratio Rule
The standard ADA requirement for ramp slope is 1:12. This means that for every 1 inch of vertical rise (the height the ramp must climb), you must have at least 12 inches (1 foot) of horizontal ramp length (run).
- Example: If your porch is 24 inches high, you need a ramp that is at least 24 feet long.
- Maximum Rise: ADA standards state that a single ramp run cannot exceed 30 inches in height. If your rise is higher than 30 inches, you must include a level resting landing.
Additional ADA Requirements
While the slope is the most critical factor, other dimensions are required for full compliance:
- Minimum Width: The clear width of the ramp must be at least 36 inches.
- Landings: Ramps must have level landings at the top and bottom. Landings must be at least as wide as the ramp and at least 60 inches (5 feet) long.
- Handrails: If a ramp has a rise greater than 6 inches or a horizontal projection greater than 72 inches, handrails are required on both sides.
- Edge Protection: Ramps and landings must have curbs or barriers to prevent wheelchairs from slipping off the edge.
Common Calculation Examples
| Rise (Height) | Required Length | Compliance Notes |
|---|---|---|
| 6 Inches | 6 Feet | No handrails needed if run < 6ft. |
| 15 Inches | 15 Feet | Standard single run. |
| 40 Inches | 40 Feet | Requires at least 1 intermediate landing. |