🧮 Ramp Slope Calculator
Real-time ramp design with ADA presets, unit controls, and a downloadable PDF.
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Choose an ADA preset or use Custom to enter a ratio like 1:X. Percent grade = (1/X)*100.
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Turns split the total run/length into two runs with a landing in between.
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Common step height is ~7 in. Example: 5 steps × 7 in = 35 in.
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Run = horizontal distance. For 1:16 and 35 in rise, run ≈ 46.67 ft.
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Ramp length = √(run² + rise²).
Minimum clear width: 36 in
Landing length: 60 in (min)
Max rise per section: 30 in
For rise > 6 in or run > 72 in, handrails on both sides are required (ADA). Below 1:20 it’s not considered a ramp.
Maximum run between landings (from 30 in max rise)
🧭 (in your selected run units)
Show step-by-step derivation
ADA slope quick table
| Slope (ratio) | Grade (%) | Max rise allowed |
|---|---|---|
| 1 : 20 (minimum) | 5.00% | 30 in (760 mm) |
| 1 : 16 (comfortable) | 6.25% | 30 in (760 mm) |
| 1 : 12 (maximum for new) | 8.33% | 30 in (760 mm) |
| 1 : 10 to < 1 : 12* | 10% to 8.33% | 6 in (150 mm) |
| 1 : 8 to < 1 : 10* | 12.5% to 10% | 3 in (75 mm) |
*For existing facilities with space limitations; steeper than 1:8 is not permitted.
Sources
• 2010 ADA Standards for Accessible Design (ramps: slope, width, landings, handrails)