Ramp Gradient CalculatorFree online other calculator — instant results, no sign-up
Calculate ramp grade from rise and horizontal run.
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About the Ramp Gradient Calculator
The Ramp Gradient Calculator calculates a ramp’s percentage grade from its vertical rise and horizontal run, both entered in metres. Use it to assess the steepness of a proposed or existing ramp, measuring run along the ground rather than along the sloping surface.
- Rise (m)
- The vertical height difference between the ramp’s lower and upper ends, measured in metres; the default is 0.3 m.
- Horizontal run (m)
- The horizontal distance covered by the ramp, not its sloping surface length, measured in metres; the default is 3.6 m.
Formula and method
G = (h / r) × 100
- GRamp gradient expressed as a percentage (%).
- hVertical rise in metres (m).
- rHorizontal run in metres (m), which must be greater than zero.
Divide the rise by the horizontal run, then multiply by 100 to express the ratio as a percentage. With the default inputs, G = (0.3 / 3.6) × 100 = 8.333333…%, displayed as 8.333333%.
Worked example
These are the calculator's starting values and the results it actually produces for them.
Inputs
- Rise0.3 m
- Horizontal run3.6 m
Results
- Result8.333333 %
How to use the Ramp Gradient Calculator
- 1Measure the vertical height difference between the ramp’s endpoints in metres.
- 2Measure the horizontal distance between those endpoints in metres, rather than the distance along the ramp surface.
- 3Enter the measurements in Rise (m) and Horizontal run (m); keep 0.3 and 3.6 to reproduce the default example.
- 4Check that the horizontal run is greater than zero and both measurements use metres.
- 5Read the Result row as percentage grade; the default inputs produce 8.333333%.
Reading your result
The Result row shows the ramp’s grade as a percentage, not an angle in degrees. The default result of 8.333333% means the rise is approximately 8.333333% of the horizontal run. The same default geometry has a rise-to-run ratio of 1:12. Higher positive percentages indicate steeper ramps, while a zero rise gives a level surface.
Limitations
This calculation assumes a straight ramp with a uniform slope; for a ramp whose slope varies, endpoint measurements give only its overall average grade. Horizontal run must be positive, and the displayed precision does not imply equally precise measurements. The calculator does not evaluate cross slope, landings, handrails, surface traction, load capacity, or compliance with accessibility and building requirements. Check the rules applicable to your location and project before using a grade for construction.
Common questions
Can I enter the length measured along the ramp as the horizontal run?+
No. The formula requires the horizontal projection of the ramp. The sloping surface is longer than the horizontal run for a nonzero rise, so using it would underestimate the grade.
Why do a 0.3 m rise and a 3.6 m horizontal run give 8.333333%?+
Dividing 0.3 by 3.6 gives 0.08333333…, and multiplying by 100 gives 8.333333…%. The result is displayed to six decimal places as 8.333333%.
Is the default ramp gradient the same as a 1:12 slope?+
Yes. The default rise-to-run ratio is 0.3:3.6, which simplifies to 1:12. This means one unit of vertical rise for every twelve units of horizontal travel.
Does an 8.333333% result mean the ramp meets accessibility requirements?+
Not by itself. Grade is only one requirement, and applicable rules may also address rise per segment, landings, width, handrails, and surface conditions. Check the exact unrounded dimensions and the requirements for your location and intended use.
Does the calculator save my information?+
Calculations run in your browser. While signed in, inputs and results are automatically recorded in account history; saving a result creates a separate saved record.
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Results are estimates for informational purposes and are not financial, medical or legal advice.