Question: how do you calculate the slope of a wheelchair ramp?
Answer: For commercial use when somebody is sitting in the wheelchair or scooter while it climbs the ramp, ADA recommends a 1:12 slope, which means that every 1" of vertical rise requires at least 1' (12") of ramp length (5 degrees of incline). Example: A 24" rise requires a minimum ramp length of 24' (288") (24 divided by 1).