Ramp Slope for 12 in Rise over 12 ft Run
A ramp with a 12-inch rise over a 144-inch (12-foot) horizontal run achieves a grade of 8.3%, compliant with ADA standards.
How to use this tool
- Enter the rise (vertical height) and run (horizontal distance) in inches.
- The calculator outputs the slope ratio (e.g. 1:12), grade percentage, and actual ramp surface length.
- ADA-compliant ramps must not exceed 1:12 slope (8.33% grade).
Find the slope percentage and angle for a ramp that spans 12 feet horizontally to climb a 12-inch step or threshold.
Frequently asked questions
- What is the ADA ramp slope requirement?
- ADA requires a maximum slope of 1:12 (one inch of rise for every 12 inches of run), which equals an 8.33% grade.
- How do I calculate ramp grade percentage?
- Divide the rise by the run, then multiply by 100. For example, a 6-inch rise over a 72-inch run is 6/72×100 = 8.33% grade.