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Enter the total rise and choose the rule set the ramp has to meet. The calculator multiplies the rise by the slope ratio to get the horizontal run, splits the run where the rule set limits the rise or length between landings, and adds the landings to give the total straight length.
- Slope used
- Horizontal run of sloped sections
- Ramp runs and intermediate landings
- Total straight length, including top and bottom landings
Total straight ramp length for common rises
Horizontal run plus all landings, for a straight ramp at each rule set's steepest allowed slope.
| Rise | ADA 2010 | IRC 2024 | NBC barrier-free | Ontario barrier-free | Part 9 house | CSA B652 | VA SAH |
|---|---|---|---|---|---|---|---|
| 6 in (152 mm) | 4.88 m (16 ft 0 in) | 3.66 m (12 ft 0 in) | 5.23 m (17 ft 2 in) | 5.23 m (17 ft 2 in) | 3.72 m (12 ft 3 in) | 5.89 m (19 ft 4 in) | 4.95 m (16 ft 3 in) |
| 12 in (305 mm) | 6.71 m (22 ft 0 in) | 5.49 m (18 ft 0 in) | 7.06 m (23 ft 2 in) | 7.06 m (23 ft 2 in) | 5.25 m (17 ft 3 in) | 8.17 m (26 ft 10 in) | 6.86 m (22 ft 6 in) |
| 18 in (457 mm) | 8.54 m (28 ft 0 in) | 7.31 m (24 ft 0 in) | 8.89 m (29 ft 2 in) | 8.89 m (29 ft 2 in) | 6.77 m (22 ft 3 in) | 10.46 m (34 ft 4 in) | 8.76 m (28 ft 9 in) |
| 24 in (610 mm) | 10.37 m (34 ft 0 in) | 9.14 m (30 ft 0 in) | 10.72 m (35 ft 2 in) | 10.72 m (35 ft 2 in) | 8.30 m (27 ft 3 in) | 14.54 m (47 ft 9 in) | 10.67 m (35 ft 0 in) |
| 30 in (762 mm) | 12.19 m (40 ft 0 in) | 10.97 m (36 ft 0 in) | 13.89 m (45 ft 7 in) | 14.24 m (46 ft 9 in) | 9.82 m (32 ft 3 in) | 16.83 m (55 ft 3 in) | 14.10 m (46 ft 3 in) |
| 36 in (914 mm) | 15.55 m (51 ft 0 in) | 12.80 m (42 ft 0 in) | 15.72 m (51 ft 7 in) | 16.07 m (52 ft 9 in) | 11.34 m (37 ft 3 in) | 19.12 m (62 ft 9 in) | 16.00 m (52 ft 6 in) |
How is ramp length calculated?
Ramp run equals rise multiplied by the slope ratio. At 1:12, a 24 in (610 mm) rise needs 24 x 12 = 288 in, or 24 ft (7.32 m), of horizontal run. Measure the rise vertically from the ground where the ramp will start to the surface at the top, usually the door threshold. Use a tape or laser measure for this one.
The run is the horizontal distance the ramp covers, not the length along the sloped surface. Landings are extra: every rule set needs one at the top and bottom, and most need intermediate landings on long ramps.
Which rule set should I choose?
Choose the one the project is held to:
- US houses: the IRC applies where a state or city has adopted it, and the ADA numbers are the usual design benchmark. See wheelchair ramp requirements for homes in the US.
- Canadian houses: Part 9 of the building code applies, with a 1 in 10 maximum. The barrier-free rules and CSA B652 are gentler design targets. See wheelchair ramp requirements in Canada.
- Funded projects: the funder's specification can be stricter than the code, as the VA's 8 percent limit is.
For the rules side by side, see ADA vs Canadian building codes.
What does the calculator assume?
The calculator assumes a straight ramp with one landing at the top and one at the bottom. A switchback or L-shaped ramp needs turning landings sized for the turn, such as 60 x 60 in (1,525 x 1,525 mm) under the ADA or 1,800 x 1,800 mm (70.9 x 70.9 in) under CSA B652, so its footprint differs from the straight length shown.
It uses the steepest slope each rule set allows. A gentler slope means a longer ramp but an easier climb, and CSA B652 allows anything from 1:15 to 1:20.
The landing lengths are the minimums each rule set states. Under Part 9 of the Canadian codes, a straight landing need be no longer than the ramp width or 1,100 mm (43.3 in), whichever is less, so a narrow house ramp can have a shorter landing than the calculator shows.
Common questions
How long does a ramp need to be for 3 steps?
Measure the actual rise, because step heights vary. Three steps of 7 in (178 mm) give a 21 in (533 mm) rise, which needs 21 ft (6.4 m) of run at 1:12, plus landings.
Can I make the ramp shorter by making it steeper?
Only within the rule set's maximum. A ramp at a house in Canada can be as steep as 1 in 10 under Part 9, and the IRC allows 1:8 for a ramp that does not serve the required egress door. A steeper ramp is harder to climb and to control on the way down.
Spotted an error? Read our corrections policy.
Cite as: Home Adapt Guide Team. (2026, October 15). Wheelchair ramp length calculator. Home Adapt Guide. https://homeadaptguide.com/tools/ramp-length-calculator/