About this tool
The Ramp Slope & ADA Compliance Calculator turns a vertical rise into a ramp run, slope ratio, percent grade and angle, and checks the result against accessibility limits. Enter the rise in inches, choose whether to design to a target slope or evaluate a run you already have, pick the standard to check against, and optionally give the ramp width. All calculations run in your browser.
A slope ratio of 1:X means the run equals rise × X, so an ADA ramp at 1:12 turns a 24" rise into a 288" (24 ft) run. Percent grade is (rise ÷ run) × 100 and the angle is atan(rise ÷ run) in degrees; the ramp's incline length (the sloped surface) is √(rise² + run²). The pass/fail test compares the actual slope to the selected standard's maximum — ADA and IBC cap running slope at 1:12 (8.33%), while an occupied residential ramp may go to 1:8 (12.5%). In evaluate-a-run mode you can enter any run and see whether it passes.
ADA also limits a single ramp run to 30 inches of rise, so taller ramps must be split with level landings: the number of runs is rise ÷ 30 rounded up, and landings between them is runs − 1. Handrails are required when the rise exceeds 6 inches or the run exceeds 72 inches, the minimum clear width is 36 inches, and level 60-inch landings are needed top and bottom. The tool flags these requirements so you can plan a compliant, safe ramp.