ADA ramp slope calculator
Enter the rise and the standard. You get the allowed slope, ramp run, number of runs and intermediate landings.
Total length with landings
11.5 m
- Maximum allowed slope6 %
- Ramp run (horizontal)10 m
- Runs2 unit
- Intermediate landings1 unit
- Total length with landings11.5 m
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How it's calculated (visible formula)
ADA: 1:12 max slope, ≤ 30 in rise per run, 60 in landings. CTE (Spain): 10% if L ≤ 3 m, 8% if ≤ 6 m, 6% otherwise; runs ≤ 9 m
- Net geometric measurement, no waste.
- Adjustable waste % for cuts and breakage.
- Purchase rounded up to sellable units (boxes, bags, buckets, boards).
How to calculate it, step by step
- Measure the exact rise between finished levels.
- Pick the standard (ADA in the US, CTE in Spain).
- Check the maximum slope for the resulting length.
- Split into runs if over the maximum and add landings.
- Add top and bottom landings and check available space.
Worked example: 24 in (60 cm) rise under ADA
- 24 × 12 = 288 in = 24 ft (7.2 m)
- Rise ≤ 30 in → one run
→ A 24 ft ramp, no intermediate landing.
Common mistakes
- Using 1:12 without checking the 30 in max rise per run.
- Forgetting top and bottom landings (60 in long).
- Missing handrails on both sides for rises over 6 in.
Pro tips
- Use slip-resistant surfaces outdoors.
- Provide handrails both sides on rises over 6 in.
- Add 2 in edge protection so wheels can't roll off.
- If space is tight, consider a platform lift.
From calculation to quote
Add labour, overhead and your margin, and generate the professional PDF.
FAQs
- What is the ADA ramp slope?
- 1:12 maximum (8.33%) — 1 in of rise per 12 in of run.
- How long can a ramp run be?
- Each run can rise at most 30 in (about 30 ft of ramp), then a level landing.
- Residential ramps?
- 1:12 is the target; 1:16–1:20 is easier for manual wheelchairs.
- How wide must an ADA ramp be?
- 36 in clear between handrails.
- Do homes need ADA ramps?
- Private homes aren't covered by ADA, but its dimensions are a good guide.
- How big are ADA landings?
- At least 60 in long and as wide as the ramp.
Sources and standards
Maintained by Srikanta M · Formula v1.0.0 · Verified 2026-09-10 · Updated 2026-09-10 · Limits: quantity estimation, not structural design or site supervision.