ADA Ramp Calculator — Slope, Run Length & Landings (Simplified)

    Calculate ramp run length, slope percentage, and landing counts using simplified ADA slope guidance for early accessibility planning.

    Tips

    • 1:12 is the common maximum slope guideline for accessibility — gentler slopes are easier to use.
    • Plan for landings at the top and bottom, plus intermediate landings for long runs.
    • Real-world compliance can also depend on clear width, handrails, cross-slope, and site constraints.
    • Use this tool for early layout planning, then confirm with the adopted accessibility standard.

    Planning tool only — simplified ADA slope and landing assumptions. Full compliance depends on additional requirements and local amendments.

    Example Calculation

    Need to overcome a 30-inch rise at 1:12? The ramp run is 360 inches (30 feet) with landings at top and bottom — total footprint about 40 feet. For a 60-inch rise, you'd need two ramp segments with an intermediate landing, totaling about 75 feet of ramp footprint. Consider switchbacks to fit in tighter spaces.

    Quick Slope Reference

    Slope RatioSlope %
    1:128.33%
    1:166.25%
    1:205.00%

    Frequently Asked Questions

    What does 1:12 mean?

    For every 1 inch of rise, you need 12 inches of horizontal run.

    How do I estimate landings?

    A common planning approach is to add intermediate landings if a run exceeds 30 feet, plus landings at the top and bottom.

    Is 1:12 always required?

    Many projects use 1:12 as the maximum guideline, but requirements can vary by jurisdiction and situation.

    Does this calculator guarantee ADA compliance?

    No. It's a planning tool. Confirm clear width, handrails, cross slope, and other requirements in the adopted standard.

    What if the ramp is too long?

    Consider reconfiguring with switchbacks, adding intermediate landings, or exploring lifts where permitted and appropriate.

    Typical Results

    Threshold ramp(6" rise)6 ft of run
    Single step(7" rise)7 ft of run
    Full curb(30" rise (max per run))30 ft of run

    💡 If the required run exceeds 30', the ramp needs an intermediate landing — factor that into your layout.

    Common Mistakes

    • •Measuring height of curb or step incorrectly — include any door threshold height
    • •Planning the ramp length without accounting for landing space at top and bottom
    • •Forgetting handrail extensions (12" beyond top riser, 12" plus one tread depth at bottom)

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