Measure how high the ramp has to climb. You get how long it must be at the ADA’s 1:12, its runs and landings, the space it takes straight, as an L or as a U, and where the handrails go.
Your wheelchair ramp
24′ of ramp at 1:12one run rising 24″ · 34′ long with its landings · handrails on both sides
Quick answer: an ADA ramp rises at most 1:12, an inch for every foot, so it is as many feet long as the rise is in inches: a 24″ rise needs 24′ of ramp. Each run rises 30″ at most, with a level landing 60″ long at its top and bottom, 60 × 60″ where it turns, 36″ clear between the handrails, and handrails on both sides once a run rises more than 6″.
How to use the wheelchair ramp calculator
- Measure the rise: from the ground where the ramp will start straight up to the floor inside the door. Count the steps and add their heights if that is easier.
- Pick the slope. 1:12 is the steepest the ADA allows; 1:16 is gentler to push up; 1:20 is a sloped walk, not a ramp.
- Pick the shape: straight, an L with one turn, or a U that doubles back.
- Pick the rules: the ADA Standards (public buildings, and the measure to build a home ramp for a wheelchair) or the home code’s minimum. You get the ramp’s length, its runs and landings, the space it takes and its handrails, drawn from above.
- Have a ramp already? Type its length and the calculator gives its slope and whether it is too steep.
The rules behind the numbers
Slope
“Ramp runs shall have a running slope not steeper than 1:12” (2010 ADA Standards §405.2): 1″ of rise for every 12″ of ramp, measured flat. That is 8.3%, or 4.8°. “To accommodate the widest range of users, provide ramps with the least possible running slope” (Advisory 405.2). The cross slope is 1:48 at most (§405.3). Anything 1:20 or gentler is a walking surface, not a ramp (§403.3), and needs no handrails.
Runs and landings
“The rise for any ramp run shall be 30 inches (760 mm) maximum” (§405.6), so a 1:12 run is 30′ long at most. “Ramps shall have landings at the top and the bottom of each ramp run” (§405.7): level, at least as wide as the ramp, and “60 inches (1525 mm) long minimum”. A ramp that turns needs a landing “60 inches (1525 mm) minimum by 60 inches (1525 mm) minimum” (§405.7.4). At the door, the door’s own clear floor space may overlap the landing (§405.7.5).
Width, handrails and edges
“The clear width of a ramp run and, where handrails are provided, the clear width between handrails shall be 36 inches (915 mm) minimum” (§405.5). “Ramp runs with a rise greater than 6 inches (150 mm) shall have handrails” (§405.8), on both sides (§505.2), their tops 34–38″ above the ramp (§505.4), running 12″ flat past the top and bottom of each run (§505.10.1). Where there are handrails, the edges get a curb or barrier, or the ramp’s surface runs 12″ past the handrail (§405.9).
At a house: the home code
The International Residential Code asks less. A ramp to the main door slopes “not more than 1 unit vertical in 12 units horizontal” (R311.8.1); landings at the top, the bottom, at a door and where it turns are as wide as the ramp and “not less than 36 inches (914 mm)” deep (R311.8.2); a handrail goes on one side only when the ramp is steeper than 1:12 (R311.8.3). A ramp or landing more than 30″ above the ground gets 36″ guards (R312.1.1, R312.1.2). A wheelchair turns in a 60″ circle (ADA §304.3), so for a wheelchair, build the ADA’s landings.
Ramp length by rise
At 1:12, 36″ wide, by the ADA Standards; the landings are the 60″ ones:
| Rise | Ramp | Runs | Straight, with landings | As an L | As a U | At 1:20 (a walk) |
|---|---|---|---|---|---|---|
| 6″ | 6′ | 1 | 16′ | 13′ × 13′ | 13′ × 6′ | 10′ |
| 12″ | 12′ | 1 | 22′ | 16′ × 16′ | 16′ × 6′ | 20′ |
| 18″ | 18′ | 1 | 28′ | 19′ × 19′ | 19′ × 6′ | 30′ |
| 24″ | 24′ | 1 | 34′ | 22′ × 22′ | 22′ × 6′ | 40′ |
| 30″ | 30′ | 1 | 40′ | 25′ × 25′ | 25′ × 6′ | 50′ |
| 36″ | 36′ | 2 | 51′ | 28′ × 28′ | 28′ × 6′ | 60′ |
| 48″ | 48′ | 2 | 63′ | 34′ × 34′ | 34′ × 6′ | 80′ |
| 60″ | 60′ | 2 | 75′ | 40′ × 40′ | 40′ × 6′ | 100′ |
A ramp built as an L or a U always has two runs, so each rises half as much: a 12″ rise as an L is two 6″ runs, and needs no handrails by §405.8.
In an existing building with no room
| Slope | Rise at most | Section |
|---|---|---|
| 1:12 or gentler | 30″ per run | §405.2, §405.6 |
| steeper than 1:12, up to 1:10 | 6″ | Table 405.2 |
| steeper than 1:10, up to 1:8 | 3″ | Table 405.2 |
| steeper than 1:8 | never | Table 405.2 |
Four worked examples
Three steps up to the front door, 24″ in all. 24′ of ramp in one run; with a 60″ landing at the bottom and one at the door the ramp is 34′ long, with handrails on both sides.
A 36″ porch, in a narrow side yard. Over 30″, so 2 runs of 18′, each rising 18″. Doubled back as a U it takes 28′ × 6′, with a 60″ landing where it turns.
A 12″ rise that turns a corner. 2 runs of 6′, each rising 6″, in an L 16′ × 16′ round a 60 × 60″ corner landing. Neither run rises over 6″, so no handrails are required.
A 20′ ramp for a 24″ rise. That is 1:10, 10%: too steep for new work. At 1:12 it needs 24′, 4′ more.
Common ramp mistakes
- Measuring the rise at the house. Measure from the ground where the ramp will start; a yard that falls away from the house adds rise.
- Counting the landings as ramp. They are level, and they add 5′ each to the length.
- A 36″ ramp with the rails inside it. 36″ is the clear width between the handrails, so the deck is wider.
- No landing at the door. A wheelchair needs a level place to stop and open the door.
- A turn on a sloped corner. Every change of direction is a level landing; a ramp that turns without one “can create a compound slope” (Advisory 405.7).
The ADA Standards are written for public buildings and businesses; at a private house the residential code applies, and the ADA’s numbers are the measure to build to for a wheelchair. Ask your building department whether yours needs a permit. Plan the bathroom inside with the ADA bathroom dimensions calculator, and draw the rooms the ramp leads to in the free 2D planner.
ADA bathroom sizesRead next
Wheelchair ramp questions
What are the ADA ramp requirements?
A slope of 1:12 at most, a rise of 30″ at most per run, level landings 60″ long at the top and bottom of every run and 60 × 60″ at a turn, 36″ clear between the handrails, handrails 34–38″ high on both sides of any run rising more than 6″, and edge protection (§405, §505).
What is the ADA ramp slope?
1:12 at the steepest: 1″ of rise for every 12″ of run, which is 8.3% or 4.8° (§405.2). In an existing building with no room, 1:10 is allowed for a rise of 6″ or less and 1:8 for 3″ or less; steeper than 1:8 never.
How long does a wheelchair ramp need to be?
At 1:12, one foot of ramp for every inch of rise, plus the landings: a 24″ rise needs 24′ of ramp, 34′ in a straight line with a 60″ landing at each end. At 1:20 the same rise needs 40′.
What are the ADA ramp handrail requirements?
Handrails on both sides of any run rising more than 6″ (§405.8, §505.2), their tops 34–38″ above the ramp (§505.4), continuous along each run and extending 12″ flat past its top and bottom (§505.10.1), 1½″ clear of a wall (§505.5), round rails 1¼–2″ across (§505.7.1).
How wide does an ADA ramp have to be?
36″ clear, measured between the handrails where there are handrails (§405.5). Landings are at least as wide as the ramp run that reaches them.
What are the ADA ramp landing requirements?
A level landing at the top and the bottom of each run, at least as wide as the run and 60″ long (§405.7.2, §405.7.3), 60 × 60″ where the ramp changes direction (§405.7.4), sloped no more than 1:48 so water drains.
Does a ramp at a house have to meet the ADA?
The ADA Standards are written for public buildings and businesses. At a private house the residential code applies: the IRC’s ramp to the main door is 1:12 at most with 36″ landings (R311.8). For a wheelchair user, the ADA’s 60″ landings and handrails are the measure to build to.