Wheelchair Ramp Length Calculator
One foot of ramp for every inch of rise is the ADA maximum, and for a lot of people it is still too steep. Enter the rise below to get the length, the landings that rise requires, and whether any of it fits the space you actually have.
Measure from the ground straight up to the top surface of the porch or doorway, not along the steps.
This sets the slope, and it is the input that changes the answer most.
Straight-line distance from the base of the steps to whatever stops you: a driveway, a fence, a property line.
Ramp surface
24 ft
at 1:12
Total footprint
34 ft
including a 5 ft level landing top and bottom
Steepest allowed
24 ft
ramp surface at the 1:12 ADA maximum
Why 1:12? 1:12, the ADA maximum. Workable when a helper is doing the pushing, and the steepest slope worth building.
- A rise over 6 inches means handrails on both sides, graspable and continuous, with at least 36 inches of clear ramp width between them.
This is a planning estimate, not an approval. It works out geometry from one measurement. It does not know your frost line, your door swing, which way the ramp has to turn, what the ground does, or what your city requires. Permanent ramps usually need a permit and an inspection, and local rules can be stricter than the figures above. Confirm the design with your building department or a contractor before buying materials.
How long does a wheelchair ramp need to be?
At the 1:12 ADA maximum, one foot of ramp surface for every inch of vertical rise. A 24-inch rise is 24 feet of ramp. That single sentence answers the question most people arrive with, and it is also where most ramp plans go wrong, because the number people picture is much smaller than the number the geometry produces.
Three things then make the real footprint larger. Slope is the first: 1:12 is a legal ceiling, not a comfortable grade, and someone pushing their own chair generally needs 1:16 or gentler. Landings are the second: a level five-foot landing belongs at the top and the bottom, and the standard caps any single run at 30 inches of climb, so a taller rise needs a landing partway up. Turning is the third: when the straight-line distance is not available, the ramp folds back on itself, and every change of direction needs a 60-inch square landing of its own.
Where these numbers come from
The slope and landing rules above are the 2010 ADA Standards for Accessible Design, published by the U.S. Access Board. They apply to public buildings. Private homes are governed by local building code instead, but the industry quotes these same figures for home work, and they are the numbers a contractor will use.
- 405.2
- Running slope, 1:12 maximum
- 405.6
- Rise, 30 inches maximum for any single run
- 405.7
- Landings top and bottom, 60 inches minimum length
- 405.8
- Handrails on both sides where the rise is over 6 inches
- 405.5
- Clear width, 36 inches minimum
- 405.7.4
- Turning landings, 60 by 60 inches
The gentler 1:16 and 1:20 slopes are not code. They are the widely used recommendations for someone pushing their own chair, or walking with a frame, and this page says so wherever it uses them.
Slope, in plain terms
| Slope | Who it suits | A 24″ rise becomes |
|---|---|---|
| 1:8 | Nobody, for a ramp anyone rolls down. It appears in load-ramp specs and gets misread as a mobility figure. | 16 ft |
| 1:12 | The ADA maximum. Fine with a helper pushing, or a power chair. | 24 ft |
| 1:16 | Someone propelling their own chair up it, unassisted. | 32 ft |
| 1:20 | Walkers and rollators, and anyone unsteady on their feet. | 40 ft |
The slope that matters is often the one going down, not up. A grade someone can climb with effort can still be one they cannot control on the way back, and that is the direction falls happen in.
When this stops being a DIY job
A threshold ramp is not construction. It is a moulded or modular wedge that gets placed at a doorway, and for a rise of about six inches or less it is usually the entire solution.
Above that, a ramp is a structure that carries a person. It generally needs footings below the frost line, handrails on both sides, a permit, and an inspection. Someone comfortable framing a deck can build one to a drawing. For everyone else the honest answer is that this is hired work, and the inspection is not optional either way.
Reasonable to do yourself
- Measuring the rise and the available run
- Placing a threshold ramp at a door or garage step
- Deciding which door the ramp should serve
- Calling the building department to ask what a permit needs
Hire this out
- Any permanent ramp over a six-inch rise
- Anything needing footings, a switchback, or a turn
- Ramps attached to the house structure
- Anything where the permit drawing has to be stamped
Common questions
- How long does a wheelchair ramp need to be?
- At the 1:12 ADA maximum, one foot of ramp for every inch of rise. A 24-inch rise needs 24 feet of ramp surface. For someone pushing their own chair, 1:16 is the practical target, which makes the same 24-inch rise 32 feet. Add a five-foot level landing at the top and the bottom, and another five-foot landing for every 30 inches of climb.
- What is the maximum slope for a wheelchair ramp?
- 1:12, meaning one inch of rise for every twelve inches of ramp run. That is the ADA maximum, not a comfortable target. Steeper than 1:12 is difficult to climb and, more dangerous, hard to control on the way down.
- Does a residential ramp have to meet ADA standards?
- The ADA governs public accommodations, not private homes, so a ramp at a private residence is usually not legally bound by it. Local building codes are what apply, they frequently borrow the ADA numbers, and permanent ramps generally need a permit and an inspection. Building to 1:12 or gentler is the sensible default regardless, because the slope is about whether someone can actually use the ramp.
- How much space does a ramp need if I only have a small yard?
- More than most people expect. A 30-inch rise at 1:12 is 30 feet of ramp surface before landings. When the straight-line distance is not there, the ramp turns along the house or switches back on itself. That keeps the same surface length but folds it into the space available, and it needs a 60-inch by 60-inch landing at each change of direction.
- When is a threshold ramp enough?
- For a rise of roughly six inches or less, which covers most single steps, raised door sills and garage-to-house transitions. Below that height the slope does not trigger a handrail requirement and a moulded or modular threshold ramp is usually the whole answer.
- Can I build a wheelchair ramp myself?
- A threshold ramp needs no building at all, it just gets placed. A permanent ramp is a different job: it is a structure that carries a person, it usually needs footings, a permit and an inspection, and getting the slope or the landing wrong is what tips a chair. Someone comfortable with deck framing can build one to a drawing. Most people are better served hiring it out, and the permit inspection is not optional either way.
The part you can buy today
If your rise came out under about six inches, a threshold ramp may be all you need. Anything taller is a built ramp.
Ruedamann Rubber Threshold Ramp
1.6 in rise, 3,300 lb capacity
Covers one small step at a door. Check your rise against the 1.6 in first.
Check price on Amazon
Stanley PowerLock 25 ft Tape Measure
25 ft, 1 in blade
Measures the rise, the doorway and the run. Every quote asks for these numbers.
Check price on Amazon
3M Safety-Walk Slip Resistant Tape
4 in x 15 ft roll
Rough tape for a step edge people keep missing.
Check price on Amazon
These are supplies, not the job itself. Amazon does not sell the labour, the permit or the inspection.
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