ADA Ramp Slope Calculator
Enter a total rise to size a compliant ramp — run length, landings, and handrail requirement, per the 2010 ADA Standards §405.
- Slope is within the 1:12 maximum (§405.2).
- Rise exceeds 6" — handrails required on both sides (§405.8).
- Provide top and bottom landings of ≥60" (§405.7).
The rules behind the numbers
These follow the 2010 ADA Standards §405: running slope no steeper than 1:12 (§405.2), a landing every 30" of rise (§405.6), landings at least 60" long (§405.7), and handrails on both sides when a run rises more than 6" (§405.8). These are federal new-construction values — existing-building alterations have steeper allowances.
Frequently asked questions
What is the maximum slope for an ADA ramp?
1:12 — one inch of vertical rise for every 12 inches of ramp run (about 8.33%) — for new construction under the 2010 ADA Standards §405.2. The cross slope is limited to 1:48 (§405.3). Always verify against your AHJ and adopted code.
How long does an ADA ramp need to be?
At least 12 inches of ramp run for every inch of rise (the 1:12 rule). A 24-inch rise, for example, needs at least a 24-foot run, plus level landings — so tall rises add up quickly.
When are landings and handrails required on an ADA ramp?
A level landing at least 60" long is required at the top and bottom and after every 30" of rise (§405.6–405.7). Handrails are required on both sides when a ramp run rises more than 6" (§405.8).
Related tools
- ADA Clearances & DimensionsTurning space, doors, toilets, counters, reach ranges & more — diagrams cited to the 2010 ADA Standards.
- Stair CalculatorRisers, riser height, tread run, and pitch from a rise — cited to IRC R311.7.
- Roof Pitch ConverterConvert roof slope between rise-in-12 (6:12), degrees, and percent grade.