Wheelchair Ramp Slope Calculator
Calculate the required ramp length, slope percentage, and angle for wheelchair accessibility based on ADA guidelines. Enter the vertical rise and choose the desired slope ratio to ensure compliance.
Published by:
isCalculator Editorial Team
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How to use this tool?
How to Use the Wheelchair Ramp Slope Calculator
- Enter the Rise – Type the vertical height you need to overcome in inches (e.g., 24 for a 24-inch step). Only positive numbers are accepted.
- Choose a Slope Ratio – Select from the dropdown:
- 1:12 – ADA maximum for commercial ramps (gentle).
- 1:8 – Maximum for residential use.
- 1:10 – A comfortable, gentle slope.
- 1:6 – Steep, for tight spaces.
- Click "Calculate" – The calculator instantly shows:
- Ramp Length in feet (the horizontal run needed).
- Slope % – the gradient percentage.
- Angle (°) – the ramp's incline in degrees.
- Review the Formula – Below the results, you'll see exactly how each value was computed, using your inputs.
Note: All measurements are in inches (rise) and feet (length). The calculator uses imperial units only.
Previous Results
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Frequently Asked Questions
The ADA recommends a maximum slope of 1:12 for commercial ramps, meaning for every inch of rise, you need at least 12 inches of ramp length.
Multiply the rise (in inches) by the slope ratio denominator and divide by 12 to get the ramp length in feet. For example, a 24-inch rise with a 1:12 ratio requires a 24-foot ramp.
Slope percentage is the rise divided by the run multiplied by 100. For a 1:12 ramp, slope percentage is approximately 8.33%.