ClarityHow to use this tool
- Measure the vertical height difference and enter it in metres.
- Enter the horizontal distance, not the distance measured along the sloping surface.
- Calculate the grade and angle. Compare these measurements with the requirements applicable to your project separately.
Input reference and sample values
Use the units and choices shown for each field. Sample values are provided for practice, not as recommendations.
| Input | Format and units | Sample |
|---|---|---|
| Vertical rise | Numeric value. Unit: m. Zero or positive. | 0.3 |
| Horizontal run | Numeric value. Unit: m. Must be greater than zero. | 6 |
Result for these sample inputs
5 %
- Angle (degrees)
- 2.86240523
- Sloping surface length (m)
- 6.00749532
- Rise : run
- 1 : 20
Select Try the example in the form to load these values and calculate them again. This replaces the current form inputs. Compare the result with the method and worked explanation below.
The method, explained
Grade = rise/run × 100%. Angle = arctan(rise/run).
A rise of 0.3 m over a horizontal run of 6 m gives 0.3 / 6 × 100 = 5% grade. The angle is arctan(0.05) ≈ 2.8624°. The rise-to-run ratio is 1:20, and the sloped surface length is √(6² + 0.3²) ≈ 6.0075 m.
Understanding your result
A 5% grade rises 5 units for every 100 horizontal units, equivalent to 1:20. The surface length is longer than the horizontal run for a nonzero rise. A percentage grade is not an angle in degrees.
What to keep in mind
This tool calculates geometry only. It does not determine accessibility, handrail, landing, surface or local building-code compliance. Use the horizontal run and consistent metre inputs.
Common questions
Is ramp length the same as horizontal run?
No. Ramp surface length is the hypotenuse. The horizontal run is its projection onto level ground. Using surface length as the run underestimates the grade.
How do I convert a 1:n slope to a percentage?
Divide 100 by n. A 1:20 slope is 5%; this is a geometric conversion and does not certify compliance with a particular standard.
Methodology maintained by ClarityKit. How these tools are built and checked.