Ramp Slope Calculator
Enter the ramp length and slope percentage to calculate the fall (height difference), slope ratio and whether it meets the common accessible maximum of 1:12 (8.33%) for wheelchair ramps.
Input Data
Results
At a glance:Ramp slope % = fall per 100 horizontal units. Fall = length (m) × slope% × 10 (to mm). Slope ratio = 1 : (100 ÷ slope%). Accessibility guidance commonly requires wheelchair ramps no steeper than 1:12 (about 8.33%), with a level landing at top and bottom and a limited continuous run. This calculator uses 8.33% as the default check value. Gentler ramps are safer and easier to use.
Formula
Fall (mm) = length (m) × slope% × 10
Slope ratio = 1 : (100 ÷ slope%)
Pass if slope% ≤ 8.33
$$f = L\times p\times 10$$$$R = 1:\frac{100}{p}$$$$p \le 8.33\%$$How to Use
- Enter the ramp horizontal length (m).
- Enter the slope percentage (accessible ramps commonly 8.33% = 1:12).
- The tool outputs the fall, slope ratio and check result.
Case Studies
Wheelchair access ramp
6 m, slope 8.33%.
Fall 500 mm, slope ratio 1:12, meets the access requirement.
Driveway approach
8 m, slope 5%.
Fall 400 mm, slope ratio 1:20, comfortable and passes.
FAQ
What does 1:12 mean?
For every 12 units of horizontal length, the height rises 1 unit — about 8.33%. It is the common maximum for wheelchair ramps.
Why keep ramps gentle?
Gentle ramps reduce effort and the risk of runaway wheelchairs or slipping; codes also require a resting landing on long runs.
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References
Content review: Calculatorism Construction Team. Results are for reference only; please refer to the relevant authorities for the official figures.