ADA-Compliant Ramp Calculator
Calculate ramp length, slope, and materials for ADA-compliant wheelchair ramps.
Includes concrete volume and landing requirements.
ADA ramp requirements ensure wheelchair accessibility for buildings and public spaces. The Americans with Disabilities Act (ADA) sets specific standards for slope, width, and landings.
ADA slope requirement:
Maximum slope = 1:12 (for every 1 inch of rise, 12 inches of run)
This means:
Ramp Length = Rise × 12
For a 30-inch rise: 30 × 12 = 360 inches = 30 feet of ramp length.
ADA ramp standards:
| Requirement | ADA Standard |
|---|---|
| Maximum slope | 1:12 (8.33%) |
| Minimum width | 36 inches (91 cm) |
| Maximum rise per run | 30 inches (76 cm) |
| Landing length | 60 inches (152 cm) minimum |
| Landing width | At least as wide as ramp |
| Handrails required | When rise > 6 inches |
| Edge protection | 2-inch curb or railing |
If the total rise exceeds 30 inches, you need multiple ramp runs with intermediate landings.
Number of runs formula:
Runs = Ceiling(Total Rise / 30 inches)
Concrete volume for ramp:
The ramp forms a triangular prism:
Volume = (Rise × Run × Width) / 2
For imperial: convert to cubic yards by dividing cubic inches by 46,656. For metric: result in cubic meters.
Slope percentage conversion:
- 1:12 = 8.33%
- 1:16 = 6.25% (recommended for comfort)
- 1:20 = 5.00% (ideal for self-propelled wheelchair users)
Practical tips:
- A gentler slope (1:16 or 1:20) is much easier for wheelchair users to navigate independently.
- Add non-slip surface treatment to concrete ramps.
- Ensure drainage so water does not pool on the ramp surface.
- In cold climates, consider heated ramp surfaces to prevent ice formation.
- Top and bottom landings must be level (max 2% slope for drainage).
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This calculator runs entirely in your browser, so the numbers you enter stay on your device. The math behind it is written by hand and tested against worked examples and standard references before the page goes live.
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