ADA ramp calculator
ADA wheelchair ramp calculator & compliance planner
Enter the rise you need to overcome and get the ramp run length, slope, number of runs and landings, handrail and edge-protection requirements, a cost estimate and a printable spec sheet — all in your browser, nothing uploaded.
Calculations follow the 2010 ADA Standards for Accessible Design §405 and §505. This is a planning aid, not a substitute for a design professional, a permit review or your local code authority.
Your ramp plan
24 in rise at 1:12 needs a ramp run of 24 ft (7.32 m). One run with 2 landings (top and bottom). Handrails are required because the rise is over 6 in. Minimum clear width 36 in, cross slope no steeper than 1:48, landings at least 60 in long.
Check your slope
- Ramp run length
- 24 ft7.32 m at 1:12
- Running slope
- 8.33%1:12 · 4.76° (§405.2)
- Runs
- 1 runEach run rises at most 30 in (§405.6)
- Landings
- 2 landings60 in long min, top and bottom of each run (§405.7)
- Handrails
- RequiredRun rise over 6 in (§405.8)
- Clear width
- 36 in minBetween handrails too (§405.5)
- Cross slope
- 1:48 max2.08% across the ramp (§405.3)
- Edge protection
- RequiredBoth sides of runs and landings (§405.9)
- Straight-line footprint
- 34 ft408 in if built straight (run + 2 × 60 in landings); direction changes need 60 × 60 in landings (§405.7.4)
- Cost estimate
- $3,60024 ft × $150/linear ft. Estimate only.
Residential: private single-family homes are generally not covered by ADA Title III, but local residential codes apply. The 2021 IRC (R311.8) requires 1:12 or flatter for ramps serving the required egress door, allows steeper slopes (up to 1:8) for other ramps where site constraints make it technically infeasible, landings at least 36 in deep, and a handrail on at least one side of ramps steeper than 1:12. Editions and local amendments vary — verify with your local code authority.
Ramp spec sheet
Project inputs
- Total rise
- 24 in
- Preferred slope
- 1:12 (8.33%)
- Project type
- Residential
- Cost rate
- $150 per linear ft
Computed plan
- Ramp run length
- 24 ft (7.32 m)
- Runs
- 1 run
- Landings
- 2 landings — 60 in long min, top and bottom of the run (§405.7)
- Handrails
- Required
- Clear width
- 36 in minimum (§405.5)
- Cross slope
- 1:48 maximum, 2.08% (§405.3)
- Edge protection
- Required on both sides of runs and landings (§405.9)
- Straight-line footprint
- 34 ft if built straight
- Cost estimate
- $3,600 (ramp run only, estimate)
Code references
- 2010 ADA Standards for Accessible Design, §405 Ramps and §505 Handrails.
- §405.2 slope · §405.3 cross slope · §405.5 width · §405.6 rise · §405.7 landings · §405.8 handrails · §405.9 edge protection · §405.10 wet conditions.
- ada.gov — 2010 Standards §405
This spec sheet is a planning estimate. Verify dimensions, materials and permits with a qualified designer and your local code authority before construction.
What each result is based on
- §405.2 — Ramp runs shall have a running slope not steeper than 1:12 (8.33%). The existing-sites exception in Table 405.2 allows steeper slopes only with a reduced maximum rise (6 in up to 1:10, 3 in up to 1:8); slopes steeper than 1:8 are prohibited.
- §405.3 — Cross slope of ramp runs shall not be steeper than 1:48 (2.08%).
- §405.4 — Floor and ground surfaces comply with §302; changes in level other than the running and cross slope are not permitted on ramp runs.
- §405.5 — Clear width of a ramp run, and between handrails where provided, shall be 36 in (915 mm) minimum.
- §405.6 — The rise for any ramp run shall be 30 in (760 mm) maximum — hence the split into runs and landings.
- §405.7 — Landings are required at the top and bottom of each ramp run: 60 in (1525 mm) minimum clear length, at least as wide as the widest run, 60 × 60 in where the ramp changes direction, and no steeper than 1:48.
- §405.8 — Ramp runs with a rise greater than 6 in (150 mm) shall have handrails complying with §505.
- §405.9 — Edge protection complying with §405.9.1 or §405.9.2 is required on each side of ramp runs and landings.
- §405.10 — Landings subject to wet conditions shall be designed to prevent the accumulation of water.
- §505.4, §505.10.1 — Handrails: 34–38 in above the ramp surface, on both sides (§505.2), with gripping surfaces extending at least 12 in beyond the top and bottom of each run.
Source: 2010 ADA Standards for Accessible Design, §405 (U.S. Department of Justice).
How the calculation works
Run length = rise × ratio. At the ADA maximum 1:12, one inch of rise needs 12 inches of run: a 24 in rise needs 288 in, which is 24 ft. At 1:16 it needs 32 ft and at 1:20 it needs 40 ft.
Runs = ceil(rise ÷ 30 in). The rise is split evenly across runs because §405.6 limits each run to 30 in of rise. A 35 in rise becomes 2 runs of 17.5 in; a 60 in rise becomes 2 runs of 30 in.
Landings = runs + 1. A landing is required at the top and bottom of every run (§405.7), so 1 run has 2 landings, and 2 runs have 3. Each landing is at least 60 in long, and 60 × 60 in where the ramp changes direction.
Handrails are required when a run rises more than 6 in (§405.8). For a full walkthrough of the requirements, see theADA ramp requirements guide.
Ramp questions, answered
How long does a wheelchair ramp need to be for a 24 inch rise?
At the ADA maximum running slope of 1:12 (§405.2), a 24 inch rise needs a ramp run of 24 feet: 24 × 12 = 288 inches. A gentler 1:16 ramp needs 32 feet and a 1:20 ramp needs 40 feet. Because 24 inches is under the 30 inch maximum rise per run (§405.6), it fits in a single run, with a landing at the top and at the bottom (§405.7).
How to calculate the length of a wheelchair ramp?
Multiply the total rise by the slope ratio: ramp length = rise × ratio. At 1:12 that is 12 inches of ramp for every 1 inch of rise, so a 24 inch rise needs 288 inches (24 feet). Then split the rise into runs of no more than 30 inches (§405.6) and provide a landing at the top and bottom of every run (§405.7). The calculator on this page does the whole calculation, including slope, angle, runs, landings and handrails.
How long should a ramp be for 12 steps?
It depends on the total rise, not the number of steps. Measure the vertical distance from the lower surface to the top landing. With typical residential risers of 7 to 7¾ inches (the IRC caps riser height at 7¾ inches, R311.7.5.1), 12 steps is roughly 84 to 93 inches of rise. At 1:12 that is about 84 to 93 feet of ramp run, split into 3 or 4 runs with landings between them, because each run may rise at most 30 inches (§405.6).
What is the correct slope for a wheelchair ramp?
Under the 2010 ADA Standards, the running slope of a ramp on an accessible route must not be steeper than 1:12 — 1 inch of rise for every 12 inches of run, or 8.33% (§405.2). The cross slope must not be steeper than 1:48 (§405.3). Gentler slopes are allowed and are easier to use; the ADA sets the maximum. In existing sites with space limits, Table 405.2 permits limited steeper slopes with a reduced maximum rise, and slopes steeper than 1:8 are prohibited.
How many landings does an ADA ramp need?
A landing is required at the top and bottom of every ramp run (§405.7), so a ramp with N runs has N + 1 landings. A single-run ramp has 2 landings; a 35 inch rise needs 2 runs and 3 landings, because each run may rise at most 30 inches (§405.6). Landings must be at least 60 inches long (§405.7.3), at least as wide as the widest run leading to them (§405.7.2), and 60 × 60 inches where the ramp changes direction (§405.7.4).
Do wheelchair ramps need handrails?
Under the ADA, ramp runs with a rise greater than 6 inches must have handrails (§405.8), on both sides (§505.2). Handrails must be 34 to 38 inches above the ramp surface (§505.4), continuous within each run (§505.3), and extend at least 12 inches beyond the top and bottom of the run (§505.10.1). Edge protection is required on each side of ramp runs and landings (§405.9). Residential codes differ: the 2021 IRC requires a handrail on at least one side of ramps steeper than 1:12 (R311.8.3).
Need the rules rather than the numbers? Read theADA ramp requirements, or generate anaccessibility statement for your website.