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General information on the 2010 ADA Standards for Accessible Design; it is not legal advice or a design approval. Local codes and the authority having jurisdiction can add requirements.
Short answer
Under the 2010 ADA Standards, a ramp may have a running slope of no more than 1:12 (8.33%), a cross slope of no more than 1:48, a clear width of at least 36 inches, and a rise of no more than 30 inches per run. Each run needs a level landing at top and bottom, and handrails are required on both sides when the rise is greater than 6 inches.
Definition and scope
The Standards define a ramp as a walking surface with a running slope steeper than 1:20 (5%). Anything gentler is an ordinary walking surface, and a portion of an accessible route steeper than 5% must be treated as a ramp. Under section 303.4, ramps and curb ramps are required along accessible routes to span changes in level greater than 1/2 inch; elevators and, under specified conditions, platform lifts can be an alternative. For the smaller level changes at doors, see our guide on the threshold ramp, which this page does not repeat.
How the ramp requirements work in practice
Slope: running and cross
Section 405.2 caps the running slope at 1:12, meaning 1 inch of rise for every 12 inches of run. Section 405.3 allows no other change in level on the run apart from the running slope and a cross slope of no more than 1:48. The Access Board’s technical guide recommends using the least possible slope below 1:12 and, based on a study done for the Board, suggests targets of 7.5% running slope and 1.5% cross slope for exterior ramps to leave room for construction tolerance. Those targets are recommendations, not requirements.
Rise, runs and landings
Section 405.6 limits the rise of any single run to 30 inches, with no limit on the number of runs. The guide notes that long multi-run ramps are strenuous for manual wheelchair users: landings give a place to rest but do not reduce the effort. Section 405.7 requires a level landing at the top and bottom of each run. Top and bottom landings must be at least 60 inches long and at least as wide as the widest ramp run leading to them. Where a ramp changes direction, the landing must be at least 60 by 60 inches clear. Landings may not slope more than 1:48 and should be designed to prevent water accumulation (405.10). Handrails, edge protection and posts cannot intrude into the 60 by 60 inch clearance.
Width and surface
Section 405.5 sets a minimum clear width of 36 inches, measured between handrails where they are provided. Life safety codes may require a wider egress width (see NFPA 101 Life Safety Code). Section 405.4 requires ramp runs and landings to be firm, stable and slip-resistant.
Handrails and edge protection
Section 405.8 requires handrails on both sides of a ramp run with a rise greater than 6 inches. Handrail height is 34 to 38 inches, and handrails extend at least 12 inches in the direction of the run at the top and bottom (they may turn or wrap on the continuous inside rail of a switchback ramp). Section 405.9 requires edge protection on each side of a ramp run and landing. It can be a surface extending at least 12 inches beyond the inside face of the handrail, a curb at least 4 inches high, or a rail or barrier that prevents passage of a 4 inch diameter sphere.
Requirement checklist: what to measure
| Section | Element | Requirement | What to check |
|---|---|---|---|
| 303.4 | When a ramp is needed | Level change greater than 1/2 inch on an accessible route | Total change in level along the route |
| 405.2 | Running slope | 1:12 maximum (8.33%) | Slope along the direction of travel |
| 405.3 | Cross slope | 1:48 maximum | Slope across the ramp width |
| 405.4 | Surface | Firm, stable, slip-resistant | Runs and landings |
| 405.5 | Clear width | 36 inches minimum, between handrails if provided | Narrowest point, including handrail intrusion |
| 405.6 | Rise per run | 30 inches maximum | Vertical rise of each run, not the whole ramp |
| 405.7 | Landings | 60 inches long minimum; 60 by 60 inches where direction changes; level to 1:48 | Top, bottom and every turn |
| 405.8 | Handrails | Both sides if rise exceeds 6 inches; 34 to 38 inches high; 12 inch extensions | Height, both sides, extensions |
| 405.9 | Edge protection | 12 inch surface extension, 4 inch curb, or barrier stopping a 4 inch sphere | Each side of runs and landings |
Worked arithmetic from the stated values
- A rise of 30 inches (the maximum for one run) at 1:12 needs a run of 30 × 12 = 360 inches, which is 30 feet.
- A rise of 6 inches at 1:12 needs 72 inches (6 feet) of run, and it is the largest rise for which handrails are not required.
- A rise greater than 30 inches must be split into two or more runs joined by landings.
- A 1/2 inch change in level is the point above which a ramp or curb ramp is required on an accessible route.
New construction versus alterations
Section 405.2 permits steeper slopes only in existing sites, buildings and facilities where space limits a 1:12 ramp. In those cases the maximum slope is 1:10 where the rise is no more than 6 inches, or 1:8 where the rise is no more than 3 inches. By the same arithmetic, a 6 inch rise at 1:10 needs 60 inches of run and a 3 inch rise at 1:8 needs 24 inches. Relief from handrail extensions and curb-ramp side flares (flares no steeper than 1:12) also exists for alterations.
Where it matters for labs and clinics
The Standards apply to accessible routes, so a ramp that is too steep or lacks landings undermines the route to every room behind it, including treatment rooms and laboratories. Work areas get specific relief: in employee work areas of 1,000 square feet or more, ramp width may be reduced below 36 inches by essential work equipment, and handrails may be installed after construction as needed. For the equipment these routes serve, see our guides to what a wheelchair is and the exam table and its accessible heights.
Common misunderstandings
Is the limit 30 feet or 30 inches?
The limit in 405.6 is 30 inches of rise per run, not 30 feet of length. At 1:12, a 30 inch rise happens to need 30 feet of run, which is the source of the mix-up.
Are handrails always required?
No. Handrails on both sides are required when the rise is greater than 6 inches. Edge protection under 405.9 is a separate requirement that applies to the sides of runs and landings.
Is 1:12 the recommended slope?
It is the maximum. The Access Board’s guide recommends the least possible slope and suggests 7.5% running slope for exterior ramps as a tolerance target.
Does a landing make a long ramp easier?
Landings provide rest and a place to turn, but the Board’s guide notes they do not reduce the effort of the climb.
FAQ
What slope is required for an ADA ramp?
1:12 maximum running slope (8.33%) and 1:48 maximum cross slope in new construction; 1:10 or 1:8 only in existing facilities with limited space and small rises.
How wide must an ADA ramp be?
At least 36 inches clear, measured between handrails where provided. Life safety codes may require more for egress.
How many inches of rise before a landing is needed?
A single run can rise no more than 30 inches. Level landings are required at the top and bottom of every run and where the ramp turns.
When are handrails required?
On both sides when the rise is greater than 6 inches, at 34 to 38 inches high with 12 inch extensions at top and bottom.
Sources
- U.S. Access Board, Guide to the ADA Standards, Chapter 4: Ramps and Curb Ramps (checked 2026-10-30).
- U.S. Access Board, Technical Guide: Ramps and Curb Ramps (PDF, checked 2026-10-30).
- U.S. Department of Justice, 2010 ADA Standards for Accessible Design (the standard itself, sections 303 and 405; checked 2026-10-30).
