Home access
Wheelchair ramp calculator: how long a ramp do I need?
At the ADA maximum slope of 1:12, every inch of rise takes a foot of ramp: a 21 in rise (about three steps) needs 21 ft of ramp, plus a level 5 ft landing at the top and bottom (2010 ADA Standards, 405).
Ramp length by rise
At the ADA maximum slope of 1:12. “Straight run” adds the 5 ft landings needed between runs; add a 5 ft level landing at the top and bottom as well.
| Rise | Ramp length | Runs | Straight run with landings | Handrails |
|---|---|---|---|---|
| 6 in | 6 ft | 1 | 6 ft | no |
| 7 in | 7 ft | 1 | 7 ft | yes |
| 12 in | 12 ft | 1 | 12 ft | yes |
| 14 in | 14 ft | 1 | 14 ft | yes |
| 18 in | 18 ft | 1 | 18 ft | yes |
| 21 in | 21 ft | 1 | 21 ft | yes |
| 24 in | 24 ft | 1 | 24 ft | yes |
| 30 in | 30 ft | 1 | 30 ft | yes |
| 36 in | 36 ft | 2 | 41 ft | yes |
| 48 in | 48 ft | 2 | 53 ft | yes |
Citing this? Link to https://toolkitcove.com/home-access/wheelchair-ramp-calculator/. Computed by our calculator. Free to reuse with a link (CC BY 4.0).
Gentler than 1:12
1:12 is the steepest the Standards allow; the Access Board’s guide recommends 7.5% (about 1:13) at most outdoors. A gentler slope is longer: a 21 in rise is 21 ft at 1:12 but 35 ft at 1:20. Choose the slope in the calculator.
How to measure the rise
- Lay a straight board level from the top step or threshold out over the ground.
- Measure straight down from the underside of the board to the ground where the ramp will start.
- On sloping ground, measure where the ramp will actually land: the rise is the total height to climb.
Questions
How long does a wheelchair ramp need to be?
12 in of ramp for every inch of rise at the ADA maximum of 1:12: a 21 in rise (about three steps) needs 21 ft of ramp, plus level landings.
What is the ADA ramp slope?
1:12 at most: 1 in of rise for every 12 in of length, an 8.33% grade (405.2).
When does a ramp need a landing?
At the top and bottom of every run, and between runs: no single run may rise more than 30 in. Landings are level and at least 60 in long; 60 × 60 in where the ramp turns.
When does a ramp need handrails?
When the rise is more than 6 in: on both sides, 34–38 in high, extending 12 in past the top and bottom.
How wide should a ramp be?
At least 36 in clear between the handrails (405.5).
Save to Pinterest · Download the pin image
