Ramp length, runs, landings and handrails from the 2010 ADA Standards
Updated October 2026
The rise is the vertical distance from the ground where the ramp will start to the surface it reaches, usually the threshold or porch floor. Measure from the actual ground at the ramp’s foot, not from a step, because ground often slopes away from a house. Choose 1:12 for the shortest ramp that meets the ADA Standards; gentler slopes are longer but easier to climb. Pick a layout with turns if the straight length will not fit.
Horizontal length = rise × slope ratio: 21 in × 12 = 252 in, or 21 ft. Runs = rise ÷ 30 in, rounded up, because ADA 405.6 limits each run to a 30-inch rise; the calculator splits the rise evenly across runs. Each run needs a level landing at its top and bottom, at least 60 in long (405.7.3), and 60 by 60 in where the ramp changes direction (405.7.4). A straight 21-in ramp therefore takes 21 ft + 5 ft + 5 ft = 31 ft of ground.
| Item | 2010 ADA Standard |
|---|---|
| Running slope | 1:12 maximum (405.2); in existing sites, 1:10 for up to a 6-in rise or 1:8 for up to 3 in where space requires; steeper than 1:8 prohibited |
| Cross slope | 1:48 maximum (405.3) |
| Clear width | 36 in minimum, measured between handrails (405.5) |
| Rise per run | 30 in maximum (405.6) |
| Landings | Top and bottom of every run; 60 in long; 60 × 60 in at turns; as wide as the ramp (405.7) |
| Handrails | Both sides when a run rises more than 6 in (405.8, 505.2); 34–38 in high (505.4); extend 12 in beyond the top and bottom of each run (505.10.1) |
| Edge protection | A curb or barrier that stops a 4-in sphere, or the surface extended 12 in beyond the handrail (405.9) |
| Situation | Slope | Ramp length | Runs | Landings | Straight length with landings | Handrails |
|---|---|---|---|---|---|---|
| Three steps, 21-in rise (default) | 1:12 | 21 ft | 1 | 2 | 31 ft | Yes |
| 24-in rise | 1:12 | 24 ft | 1 | 2 | 34 ft | Yes |
| 36-in porch: two runs | 1:12 | 36 ft | 2 | 3 | 51 ft | Yes |
| 36-in porch at a gentler 1:16 | 1:16 | 48 ft | 2 | 3 | 63 ft | Yes |
| 60-in deck: two runs | 1:12 | 60 ft | 2 | 3 | 75 ft | Yes |
| Existing storefront, 6-in rise at 1:10 | 1:10 | 5 ft | 1 | 2 | 15 ft | No |
A 60-inch deck needs 60 ft of ramp in two runs with three landings, 75 ft in a straight line, which rarely fits; a switchback folds it into a footprint of about half the length, with 60 × 60-in turning landings. A gentler 1:16 slope adds a third to the length.
The 2010 Standards set minimum requirements for newly built or altered state and local government facilities, public accommodations and commercial facilities. A ramp at a private home is generally governed by the local residential building code instead, but the ADA figures are the common reference for a ramp a wheelchair user can climb independently, and many contractors and kit makers design to them. Check with your local building department before building: many require a permit for ramps attached to a house.
It does not design the structure (footings, joists, decking), check local code differences, or size landings for door swings, which ADA 405.7.5 lets overlap with door maneuvering space. Portable and vehicle ramps for scooters follow their manufacturers’ ratings, not ADA 405. For a permanent ramp, a contractor or occupational therapist can check fit, surface and drainage.
Measuring to the top of the step instead of the ground. The ramp starts at the ground, so measure the full rise there.
Forgetting landings. A 36-in rise is not 36 ft of ramp: it is two runs plus three 5-ft landings, 51 ft in a straight line.
Using 1:12 as a target for every user. It is a maximum. The Access Board’s advisory note recommends the least possible running slope.
Skipping handrails on short ramps. Any run rising more than 6 in needs handrails on both sides.