Wheelchair Ramp Calculator
Enter the height you need to climb and choose a slope to get the ramp length, along with how many resting landings the run requires.
A ramp that's too steep is unsafe and hard to use; one that's too shallow takes up a lot of space. The Americans with Disabilities Act (ADA) sets the standard for accessible ramps at a 1:12 slope — one foot of ramp for every inch of rise — which is the safe default for anyone using a ramp unassisted. This calculator turns your rise into the ramp length and tells you when the run is long enough to need a level resting landing.
How to size a wheelchair ramp
At a 1:12 slope, each inch of vertical rise needs 12 inches (one foot) of ramp, so the run in feet equals the rise in inches. Steeper slopes shorten the ramp but are only appropriate with assistance or for unoccupied equipment. ADA also requires a level landing at least every 30 inches of rise.
At 1:12 → Run (ft) = Rise (in)
Landings = one every 30 in of rise
| Slope | Use | Run per 1 in rise |
|---|---|---|
| 1 : 12 | ADA — public, unassisted | 12 in (1 ft) |
| 1 : 10 | Occupied, with a helper | 10 in |
| 1 : 8 | Unoccupied equipment only | 8 in |
Worked example
A 24-inch porch at the ADA 1:12 slope:
| Run = 24 in × 12 ÷ 12 | 24 ft |
| Landings (30 in each) | 0 needed |
Don't forget landings and width
ADA ramps need a level landing at the top and bottom, and one partway up whenever a single run climbs more than 30 inches — so a tall porch becomes a switchback of ramp sections and platforms. Landings should be at least 60 inches long, and the ramp itself at least 36 inches wide between rails. For a permanent ramp, always check local building codes and permit requirements before you build.