Ramp slope calculator (%, angle and ratio)
Calculate a ramp's slope in percentage, angle and ratio — and see if it is accessible.
Slope = rise ÷ run × 100. For accessibility, the target is up to 8.33% (a 1:12 ratio). Steeper ramps need landings and handrails.
How the calculation works
The slope in percent is rise ÷ run × 100. The angle is arctan(rise ÷ run). The 1:X ratio shows how many meters of ramp per meter of height. For wheelchairs, the standard asks for at most 8.33% (1:12).
Examples
- Overcome a 0.5 m rise with an accessible ramp (8.33%): length = 6 m.
- A 1 m rise over 8 m: 12.5% (steep for a wheelchair).
Frequently asked questions
What is the max slope for an accessible ramp?
The common standard is 8.33% (1:12). Up to 10% may be tolerated on short runs with landings.
How does ramp length change with slope?
The gentler the slope, the longer the ramp for the same height. Accessibility requires long ramps, hence rest landings.
Does a ramp need handrails?
Per accessibility codes, yes — two-height handrails and landings on long ramps.
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Updated on June 30, 2026 · by Rafael Rossi · Methodology & sources