Ramp Slope Calculator
Compute ramp length from a rise at 1:12 ADA slope, or turn rise and run into ratio, angle, and grade.
Processed locally in your browser — nothing is uploaded.
Inches of run per inch of rise
Enter the rise to size the ramp.
About Ramp Slope Calculator
In length mode, enter the rise and a slope ratio — 1:12 is the ADA maximum, with 1:16 and 1:20 presets for gentler ramps — and get the required horizontal run. In slope mode, enter a rise and run to get the ratio, angle, and percent grade, with a flag whenever the result is steeper than 1:12.
Common uses
- Size a wheelchair ramp for a 24 in porch rise
- Check whether an existing ramp meets the ADA slope limit
Example
Input
24 in rise at 1:12
Output
24 ft of ramp (288 in of run)
Limitations
- ADA also requires landings every 30 in of rise, minimum widths, and handrails — this tool only covers slope