Search for a wheelchair ramp and every listing quotes the same ratio: 1:12, one inch of rise for every twelve inches of run. It is a real number with a real source. It is section 405.2 of the ADA Standards for Accessible Design, and it sets the maximum running slope for a ramp on an accessible route, roughly 8.33 percent.
What the listings do not say is that the Department of Justice applies those standards to government facilities, public accommodations and commercial facilities. Its own regulation, printed alongside the 2010 Standards, says that where a commercial facility sits inside a private residence, the portion used exclusively as a residence is not covered. So the number people size their front steps with is borrowed from a rulebook that does not govern front steps. It is still the best available yardstick, but that changes how to use it.
Trend Signal
50/100 Steady momentum
- Emerging
- Rising
- Mainstream
- Peaking
- Cooling
A stable rule set that most home buyers are applying outside its legal scope
The 1:12 slope everyone quotes comes from section 405 of the ADA Standards, which the Department of Justice applies to government facilities, public accommodations and commercial facilities, not to the part of a private residence used as a residence.
Our editorial reading of the cited data, not a forecast. How it is scored
By the numbers
- 1:12Maximum running slope for a ramp on an accessible route under the ADA StandardsU.S. Access Board
- 30 inMaximum rise for a single ramp run before a level landing is requiredU.S. Access Board
- 36 inMinimum clear width of a ramp run, measured between handrails where providedU.S. Access Board
- Jan 2020Date New York City began requiring portable entrance ramps to meet code or get a waiverNYC Mayor’s Office for People with Disabilities
Where the 1 in 12 number comes from
The Access Board publishes the plain-language guide to the ADA Standards, and chapter 4 covers ramps. Section 405.2 caps the running slope at 1:12 and the cross slope at 1:48. Section 405.5 sets a minimum clear width of 36 inches, measured between handrails where provided. Section 405.6 caps a single ramp run at 30 inches of rise, with no limit on how many runs a ramp can have.
Landings are where most home ramps go wrong. Section 405.7 requires a level landing at the top and bottom of every run, and where a ramp changes direction the intermediate landing has to be at least 60 inches by 60 inches clear. Section 405.8 requires handrails on both sides once the rise is greater than 6 inches, with 12-inch extensions at the top and bottom; section 505.4 of the same standards puts the top of the gripping surface 34 to 38 inches above the ramp surface. Section 405.9 requires edge protection along runs and landings: curbs at least 4 inches high, barriers, or a surface extended at least 12 inches beyond the handrails.
The standards also allow steeper slopes, but only in a narrow case. The exception to section 405.2 applies at existing sites, buildings and facilities where a steeper slope is necessary due to space limitations. Table 405.2 then permits a slope steeper than 1:12 but no steeper than 1:10 for a rise of 6 inches maximum, and steeper than 1:10 but no steeper than 1:8 for a rise of 3 inches maximum. Anything steeper than 1:8 is prohibited. That table is why a rubber threshold ramp two inches tall can be far steeper than 1:12 and still be defensible.
One ratio, four constraints. Slope, rise per run, width and landings all have to work at once.
What the standard does not cover
The Department of Justice published the 2010 Standards on September 15, 2010, and they became the required standard for construction and alterations starting on or after March 15, 2012. They set minimum requirements for newly designed, constructed or altered state and local government facilities, public accommodations and commercial facilities. A private house is none of those, and the Justice Department’s title III regulation, printed alongside the Standards, says that when a commercial facility is located in a private residence, the portion used exclusively as a residence is not covered.
Payment is a separate rulebook again. Chapter 15, section 110.1 of the Medicare Benefit Policy Manual, revision 13889 issued July 30, 2026, puts self-help devices such as safety grab bars in the group it treats as nonmedical, and classifies elevators and stairway elevators as comfort or convenience items. The word ramp does not appear anywhere in that chapter, so the manual neither includes nor excludes one.
The practical effect for a homeowner is that no federal accessibility standard governs a ramp at a private house. The ADA text is simply the specification everyone has, which is why every listing quotes it.
Doing the arithmetic for a real doorstep
Measure the rise first, at the point where the ramp will land, and measure it with a level rather than from the step face. Then the 1:12 ratio gives a minimum length, and the 30-inch rise limit tells you whether one run is enough.
| Rise to climb | Length at 1:12 | What the ADA allows instead |
|---|---|---|
| 2 in, a door threshold | 2 ft | Up to 1:8 at existing sites, for a rise of 3 in or less |
| 6 in, one step | 6 ft | Up to 1:10 at existing sites, for a rise of 6 in or less |
| 12 in, two steps | 12 ft | No steeper option; handrails required both sides |
| 24 in, a low porch | 24 ft | No steeper option; still one run under the 30 in limit |
| 30 in, the run limit | 30 ft | A level landing is required before any further rise |
A two-step porch needs a ramp longer than most driveways are wide. That is the number that changes plans.
One city wrote a rulebook for portable ramps
Portable ramps get treated as a shortcut, and one jurisdiction has written down what that shortcut has to do. This is a New York City program and nothing more. Local Law 122 of 2019 required that from January 1, 2020, any building owner in that city using or planning to use a portable ramp at an inaccessible entrance either comply with the New York City Building Code ramp requirements or submit a waiver application to the city Department of Buildings.
The city’s guidance restates the familiar numbers, including the 1:12 slope and the 36-inch clear width, and adds one: a maximum ramp run of 30 feet. Only buildings in existence or permitted before July 1, 2008 may use portable ramps there; buildings constructed after that date must provide accessible entrances.
One more requirement is worth borrowing for a house, even though it binds nobody outside that city. By March 1, 2020 those buildings had to post a sign at the inaccessible entrance saying a portable ramp is available, with a telephone number a person can call to request it. A portable ramp that lives in a garage is only useful if the person who needs it knows it exists.
What to check on a ramp listing
Ramp listings tend to lead with length and weight capacity and bury everything else. These are the specifications that determine whether the thing works.
- Rated capacity, and whether it covers the occupant plus the chair plus anyone pushing.
- Length against your measured rise, not against the number of steps.
- Usable width against the wheelbase, remembering the ADA figure of 36 inches is measured between handrails.
- Whether the ramp has raised side edges, which is the portable equivalent of the curb the standards require.
- How the top attaches, and whether the attachment needs drilling into a threshold or a deck board.
- Folded weight, because a ramp too heavy to move is a permanent ramp with no footings.
- Whether traction is a coating that wears off or a punched or extruded pattern.
What to watch next
- Updates to the Access Board guide to the ADA Standards, which is where the ramp figures are restated in plain language
- Local rules following New York City’s Local Law 122 model, which set conditions on portable ramps at entrances
- Any change to the Medicare durable medical equipment definition that would bring home access work inside the benefit
Where to start
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Ramp types by the rise they are meant to cross
| Product type | Good fit for | Where to look |
|---|---|---|
| Rubber threshold ramp | Fits a single doorway lip | See listings on AmazonOpens Amazon search results, not one listing: check the model on the product page. |
| Folding portable ramp | Fits two or three steps | See listings on AmazonOpens Amazon search results, not one listing: check the model on the product page. |
| Telescoping track ramps | Fits loading into a vehicle | See listings on AmazonOpens Amazon search results, not one listing: check the model on the product page. |
Product types that fit the trend described above, not tested models. Check the exact listing before you buy. How we pick them.
Rubber threshold ramp
Where to look: Amazon
For a small rise, the standards themselves allow a steeper slope, which is why a short rubber wedge is a legitimate answer rather than a compromise.
- No assembly
- Matches the slope Table 405.2 allows for small rises
- Only works to a few inches
- Can shift if it is not anchored
Folding portable ramp
Where to look: Amazon
At 1:12, three 8-inch steps want 24 feet of ramp. A folding ramp that is much shorter than that is steeper than the standard, deliberately.
- Folds for storage
- Single piece so the wheels cannot slip between tracks
- Heavy at longer lengths
- Needs a level landing at both ends
Telescoping track ramps
Where to look: Amazon
Tracks are the vehicle solution. They are lighter to carry, but there is nothing between them, so alignment becomes the safety feature.
- Each track is carried separately
- Adjustable length
- No surface between the tracks
- Wheel spacing has to match
More: Aging and Accessibility trends and how the Trend Signal is scored.
Sources
- Guide to the ADA Standards, Chapter 4: Ramps and Curb Ramps — U.S. Access Board
- 2010 ADA Standards for Accessible Design — U.S. Department of Justice
- Portable Ramps at Entrances in Prior Code Buildings — NYC Mayor’s Office for People with Disabilities
- Medicare Benefit Policy Manual, Chapter 15 — CMS
- Durable medical equipment coverage — Medicare.gov
- Facts about older adult falls — Centers for Disease Control and Prevention
Questions readers ask
Does the ADA apply to my house?
Generally no. The 2010 ADA Standards apply to state and local government facilities, public accommodations and commercial facilities, and the Department of Justice regulation printed with them says that where a commercial facility is located in a private residence, the portion used exclusively as a residence is not covered.
How long does a ramp need to be for a 6-inch step?
At the ADA maximum running slope of 1:12, a 6-inch rise needs 6 feet of ramp run, which is our arithmetic on the standard. Table 405.2 permits up to 1:10 at existing sites for a rise of 6 inches or less, which would allow 5 feet, and handrails become required on both sides above a 6-inch rise.
When does a ramp need a landing?
Section 405.6 caps a single ramp run at 30 inches of rise, and section 405.7 requires a level landing at the top and bottom of every run. Where a ramp changes direction, the intermediate landing must be at least 60 inches by 60 inches clear.
What does the Medicare manual say about ramps?
It does not mention them. Chapter 15 of the Medicare Benefit Policy Manual names self-help devices such as safety grab bars, along with elevators and stairway elevators, as nonmedical, but the word ramp does not appear in the chapter, so there is no ramp exclusion to point to either. Ask your plan what it would do.
