calcs.homes
calcs.homes
Enter the height you need to overcome and a slope ratio to find the minimum ramp length — including whether you'll need a landing partway up.
Estimate only — full ADA compliance also requires edge protection, handrails, and specific landing dimensions.
Minimum length = rise × the slope ratio's run value — a 1:12 ratio means 12 in of ramp for every 1 in of rise. ADA guidelines also require a flat landing at least every 30 ft of horizontal run (or every 30 in of rise, whichever comes first) so a wheelchair user has a place to rest or turn.
1:12 — for every inch of rise, the ramp needs at least 12 inches of run. Steeper slopes like 1:8 are only allowed for very short rises under specific exceptions.
If the ramp run exceeds 30 ft, or the rise exceeds 30 in in one continuous run, ADA guidelines require a level landing before continuing — this calculator flags that automatically.