Wheelchair Ramp Length and Slope: 1:12, Landings and Handrails
The steepest ramp the ADA allows is 1:12: one inch of rise for each foot of ramp. A 24 inch rise needs 24 feet of ramp and a 36 inch rise 36 feet, with a level landing at the top and bottom and at least every 30 inches of rise. The wheelchair ramp calculator gives the length, the landings and the footprint for your door.
Ramp length by rise
Horizontal run needed at each slope, with the separate runs and landings at 1:12:
| Rise | 1:12 (maximum) | 1:16 | 1:20 | Runs (1:12) | Intermediate landings |
|---|---|---|---|---|---|
| 6 in | 6 ft | 8 ft | 10 ft | 1 | 0 |
| 12 in | 12 ft | 16 ft | 20 ft | 1 | 0 |
| 18 in | 18 ft | 24 ft | 30 ft | 1 | 0 |
| 24 in | 24 ft | 32 ft | 40 ft | 1 | 0 |
| 30 in | 30 ft | 40 ft | 50 ft | 1 | 0 |
| 36 in | 36 ft | 48 ft | 60 ft | 2 | 1 |
| 48 in | 48 ft | 64 ft | 80 ft | 2 | 1 |
The ADA basics
- Slope: no steeper than 1:12 (8.33%), and a rise of no more than 30 inches in any one run.
- Width: at least 36 inches clear between the handrails.
- Landings: level, at least as wide as the ramp and 60 inches long, at the top, the bottom and at each turn or change of direction.
- Handrails: on both sides for a rise over 6 inches, 34 to 38 inches high, that continue past the ends.
- Edge protection: a curb or rail so a wheel cannot roll off the side.
- Surface: firm, stable and slip-resistant, including in the rain and snow.
Residential ramps are not always bound by the ADA, but it is the sensible standard to use, and a permit may be needed. Check your local code.
Planning the route
- Measure the rise from the ground to the finished floor at the door threshold.
- Add up the length of ramp and landings and check the yard has room. A long ramp can switchback (a U-turn) on a landing.
- A gentler slope than 1:12 is much easier for a wheelchair user to climb without help: 1:16 or 1:20 if you have the room.
- Think about drainage and frost: ramps in the weather need good drainage, a non-slip surface, and a plan for clearing snow.
See also the slope and grade calculator and the stair calculator. Estimates only: check the ADA standards and your local code.
Frequently asked questions
How long does a wheelchair ramp need to be?
One foot of ramp for every inch of rise at the 1:12 maximum. A rise of 24 inches needs 24 feet; 36 inches needs 36 feet.
What is the maximum slope for a wheelchair ramp?
1:12, which is 8.33% or about 4.8 degrees, for ADA ramps. Gentler slopes of 1:16 or 1:20 are easier to push up and to use without help.
Do ramps need landings?
Yes: a level 5 × 5 ft landing at the top and bottom, and at least every 30 inches of rise. A 36 inch rise needs 2 runs and 1 intermediate landing.
How wide should a ramp be?
At least 36 inches clear between handrails under the ADA. 42 to 48 inches is more comfortable and makes turning easier.
Do I need handrails?
Yes on both sides if the rise is more than 6 inches, with edge protection at the sides so wheels cannot slip off.
More guides
Tools & materials for this project
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Estimates only. Quantities depend on your materials, site and supplier. Confirm important numbers before you order, and follow local building codes for anything structural.