Wheelchair Ramp Calculator (ADA / India Accessibility)
Plan an accessible ramp and check it against the US ADA or India’s guidelines.
Your ramp
Checks
Results are estimates from the formulas shown, not a professional design or certification. Have a qualified engineer verify anything safety-critical (structures, electrical installations, gas or pressure systems).
About the Wheelchair Ramp Calculator (ADA / India Accessibility)
Work out how long a wheelchair ramp has to be for the height you need to climb, how many runs and landings it needs, and whether it meets the rules: the US 2010 ADA Standards for Accessible Design (§303, §403, §405 and the handrails of §505) and India’s Harmonised Guidelines and Standards for Universal Accessibility in India 2021 from the Ministry of Housing and Urban Affairs — or both at once, using the stricter limit at every step.
Enter the rise and the slope — 1 : 12 by default, or any ratio, percent or angle — and the tool splits the ramp into equal runs, adds the landings, gives the total length and the handrail length, converts the slope between ratio, percent and degrees, and lists every check with its clause. It is an estimate to plan with — not a professional design.
How to use it
- Choose the rules to check — ADA (US), India (HG 2021) or both — and US or metric units.
- Enter the rise: the height from the lower ground to the upper floor or doorway, e.g.
24 inor900 mm. - Set the slope: 1 : 12 is the steepest either allows for new work; 1 : 14, 1 : 16 or 1 : 20 are easier to push up but longer. Type it as a ratio, a percent or degrees.
- Give the clear width, the landing length and, if the ramp turns at its landings, tick turns. Optionally add the cross slope, and for an existing US building with no room for 1 : 12, the existing site option (ADA Table 405.2).
- Read the runs, landings, total length and handrail length, look over the checks, and copy the plan.
Examples
One run of 24 ft (24 in of rise is within 30 in per run) · 5 ft landings at the top and bottom → 34 ft overall · handrails on both sides, 34–38 in high, about 26′ 1″ per side with the 12 in extensions
36 in is more than 30 in, so two runs of 18 in rise and 18 ft each, with a 5 ft landing between: 41 ft, or 51 ft with the top and bottom landings
Table 3.4 allows 6 m of run at 1 : 12 (500 mm of rise), so two runs of 5.4 m with a 1.5 m landing: 12.3 m, 15.3 m with the top and bottom landings · handrails on both sides at 750–900 mm, extending 300 mm
Table 3.4 would allow 15 m runs, but landings are needed at least every 9 m: three runs of 6.67 m — 20 m of ramp and two landings between them
How the ramp is planned
Horizontal length = rise ÷ slope, so at 1 : 12 every unit of rise needs 12 units of ramp: 1 ft per inch, 12 m per metre. The ramp is split into the fewest equal runs whose rise stays within the limit — 30 in per run under ADA 405.6; under HG 2021 the run length of Table 3.4 (6 m at 1 : 12, 9 m at 1 : 14, 11 m at 1 : 15, 15 m at 1 : 20, 18 m at 1 : 25, in between by straight-line interpolation as clause 3.10.2 says) and never more than 9 m between landings (3.10.5). With both selected the stricter limit wins.
Each run gets a level landing at its top and bottom, so a straight ramp of n runs has n − 1 landings between them; the overall length adds one at each end. The length along the slope is horizontal × √(1 + slope²). Handrail per side assumes rails continuous over the landings plus the end extensions — 12 in (ADA 505.10.1) or 300 mm (HG 3.11.1).
The rules checked
- ADA 2010 (2010 Standards, US Department of Justice): a ramp is steeper than 1 : 20 (106.5; flatter is a walking surface, 403.3). Running slope ≤ 1 : 12 (405.2), or in existing sites short on space up to 1 : 10 for a 6 in rise and 1 : 8 for 3 in (Table 405.2). Cross slope ≤ 1 : 48 (405.3). Clear width ≥ 36 in (405.5). Rise ≤ 30 in per run (405.6). Landings at the top and bottom of each run, as wide as the run and ≥ 60 in long (405.7), 60 × 60 in where the ramp turns (405.7.4). Handrails on both sides when a run rises more than 6 in (405.8, 505.2), 34–38 in high (505.4), extending 12 in level beyond each run (505.10.1). Edge protection (405.9). Changes in level: ¼ in may be vertical, up to ½ in bevelled at 1 : 2, more must be ramped (303).
- HG 2021 (Department of Empowerment of Persons with Disabilities; clause numbers as in chapter 3 of the guidelines’ HTML edition by the National Institute of Urban Affairs): gradients by level change — up to 15 mm 1 : 2, up to 50 mm 1 : 5, up to 200 mm 1 : 10, more 1 : 12 (Table 3.2). Run lengths by gradient (Table 3.4) and at most 4 runs (3.10.2). Clear width ≥ 1200 mm (3.10.3). Landings at the top and bottom of each run, at changes of direction and at least every 9 m, a level platform of at least 1200 × 1500 mm (3.10.5). Handrails on both sides when a run rises more than 150 mm, 750–900 mm high, continuous and extending 300 mm, 38–50 mm round and 40–60 mm from the wall (3.11.1). Edge protection: a kerb at least 75 mm high, or a barrier or rail within 75 mm of the surface (3.10.7). Curved ramps, if unavoidable, no steeper than 1 : 16 (3.10.2).
Slope as a ratio, percent and degrees
A ramp slope is rise ÷ run. 1 : 12 = 8.33 % = 4.76°; 1 : 14 = 7.14 % = 4.09°; 1 : 16 = 6.25 % = 3.58°; 1 : 20 = 5 % = 2.86°. Percent is 100 ÷ n, degrees are atan(1 ÷ n). A 1 : 48 cross slope is 2.08 %.
Limitations
- An estimate to plan with — not a professional design or an approval. The ADA Standards apply to public buildings and businesses in the US; local building codes, Indian state or municipal bye-laws and the building's owner may ask for more.
- It does not design the structure (deck framing, a concrete ramp or its foundations), surfaces, drainage, lighting or the tactile warning tiles HG 2021 asks for at the start and end of each run.
- Curved ramps and compound slopes are not covered; door landings need extra manoeuvring space (ADA 404).
- Where HG 2021's run table (Table 3.4) and its 9 m landing interval (3.10.5) differ, the shorter run is used.
Privacy
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Frequently asked questions
How long does a wheelchair ramp need to be?
At 1 : 12, 1 ft of ramp for every inch of rise (12 m for every metre), plus landings. A 24 in rise needs 24 ft of ramp; a 900 mm plinth needs 10.8 m, which HG 2021 splits into two runs with a landing.
What is the maximum slope for a wheelchair ramp?
1 : 12 (8.33 %, 4.76°) for new ramps under both the ADA Standards and HG 2021. ADA allows steeper short ramps only in existing buildings without room (Table 405.2); HG 2021 allows steeper slopes only for small changes in level: 1 : 10 up to 200 mm, 1 : 5 up to 50 mm, 1 : 2 up to 15 mm.
When does a ramp need a landing?
Under ADA at the top and bottom of every run, and a run may rise at most 30 in — so every 30 ft at 1 : 12; landings are at least 60 in long. Under HG 2021 a run at 1 : 12 may be at most 6 m long, landings are needed at least every 9 m and at every turn, and each is at least 1200 × 1500 mm.
When are handrails required on a ramp?
ADA: when a run rises more than 6 in — on both sides, 34–38 in high, extending 12 in at the top and bottom. HG 2021: when a run rises more than 150 mm — on both sides, 750–900 mm high, continuous through the landings and extending 300 mm.
How wide should a ramp be?
At least 36 in clear between the handrails under ADA 405.5, and at least 1200 mm under HG 2021 3.10.3. Landings are at least as wide as the ramp.
Do I need a ramp for a small step?
Under ADA a change in level of up to ¼ in may stay vertical and up to ½ in may be bevelled at 1 : 2; anything higher must be ramped. Under HG 2021 up to 15 mm may be bevelled at 1 : 2, up to 50 mm at 1 : 5 and up to 200 mm at 1 : 10.