How the ramp length is figured
- Slope: a ramp run can be no steeper than 1:12 (§405.2), which is 8.33% or about 4.8°. Length = rise × 12.
- Rise per run: one run can climb at most 30 inches (760 mm) (§405.6). A higher rise is split into runs; this calculator splits it evenly.
- Landings: every run needs a level landing at the top and the bottom (§405.7), at least 60 inches (1525 mm) long and as wide as the widest run that leads to it. Where the ramp turns, the landing is at least 60 × 60 inches.
- Handrails: required on both sides when a run rises more than 6 inches (150 mm) (§405.8, §505.2), with the top of the gripping surface 34-38 inches high (§505.4) and extending at least 12 inches past the top and bottom of each run (§505.10.1).
- Width and edges: at least 36 inches clear between handrails (§405.5), cross slope no steeper than 1:48 (§405.3), and edge protection on each side of runs and landings unless an exception applies (§405.9).
Steeper slopes in existing buildings
- Where space is limited in an existing site, building or facility, Table 405.2 allows steeper than 1:12 up to 1:10 for a rise of 6 inches or less, and steeper than 1:10 up to 1:8 for a rise of 3 inches or less. Steeper than 1:8 is prohibited.
- The Access Board's advisory note asks for the least possible slope. A gentler ramp like 1:16 is easier for more people but takes more length.
- A walking surface no steeper than 1:20 is not a ramp (§403.3), so the ramp landing and handrail rules don't apply to it.
ADA ramp length chart (1:12)
| Rise | Ramp length | Runs | Landings | Straight length with landings between runs |
|---|---|---|---|---|
| 6 in | 6 ft | 1 | 2 | 6 ft |
| 12 in | 12 ft | 1 | 2 | 12 ft |
| 18 in | 18 ft | 1 | 2 | 18 ft |
| 24 in | 24 ft | 1 | 2 | 24 ft |
| 30 in | 30 ft | 1 | 2 | 30 ft |
| 36 in | 36 ft | 2 | 3 | 41 ft |
| 48 in | 48 ft | 2 | 3 | 53 ft |
| 60 in | 60 ft | 2 | 3 | 65 ft |
| 72 in | 72 ft | 3 | 4 | 82 ft |
Landings count the top and bottom. The last column adds 60 inches for each landing between runs; top and bottom landings come on top of that.
These figures come from the 2010 ADA Standards for facilities the ADA covers. For a ramp at a private home, check your local building code. Requirements vary.
Frequently asked questions
How long does a wheelchair ramp need to be?
At the ADA maximum slope of 1:12, every inch of rise needs 12 inches of ramp, so a 24-inch rise needs 24 feet of ramp. One run can rise at most 30 inches (§405.6), so a higher rise is split into runs with a 60-inch landing between them.
When does an ADA ramp need a landing?
Every ramp run needs a level landing at the top and the bottom (§405.7), at least 60 inches long and at least as wide as the ramp. Where the ramp changes direction, the landing must be at least 60 by 60 inches.
When are handrails required on a ramp?
When a ramp run rises more than 6 inches (§405.8). Then both sides need handrails with the top of the gripping surface 34 to 38 inches high, extending at least 12 inches beyond the top and bottom of each run (§505).
Can a ramp be steeper than 1:12?
Only in existing sites, buildings and facilities where space is limited: steeper than 1:12 up to 1:10 for a rise of 6 inches or less, and up to 1:8 for a rise of 3 inches or less (Table 405.2). A slope steeper than 1:8 is prohibited.