1. What is Wheelchair Ramp Slope Ratio?

Definition: The slope ratio (R) is the relationship between the ramp length (L) and the height change (H) it overcomes.

Purpose: This calculation ensures ramps meet accessibility standards and are safe for wheelchair users.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( R \) — Slope ratio (unitless)
• \( L \) — Ramp length (feet)
• \( H \) — Height change (feet)

Explanation: The ratio represents how many feet of ramp length are needed per foot of vertical rise.

3. Importance of Slope Ratio

Details: ADA guidelines recommend a maximum slope of 1:12 (1 inch rise per 12 inches of ramp) for wheelchair accessibility.

4. Using the Calculator

Tips: Enter the ramp length and height change in feet. Both values must be > 0. The result shows the slope ratio (e.g., 12:1).

5. Frequently Asked Questions (FAQ)

Q1: What is the maximum recommended slope ratio?
A: ADA recommends 1:12 maximum (1 unit of rise per 12 units of run) for commercial ramps.

Q2: How does this relate to slope percentage?
A: Slope percentage = (H/L) × 100. A 1:12 ratio equals about 8.33% slope.

Q3: When would I need a gentler slope?
A: For manual wheelchair users, steeper slopes require more effort. 1:16 or 1:20 may be preferable when space allows.

Q4: What about residential ramps?
A: Residential ramps may use 1:12 or slightly steeper (1:10) if space is limited, but this may not meet ADA standards.

Q5: Does this include landing requirements?
A: No, remember to include level landings at top, bottom, and turns in your total ramp design.