Slope and Grade Calculator
Enter a slope as rise and run, a percent grade, or an angle in degrees. The calculator converts to every other form and gives the 1:N ratio and slope distance.
How to convert a slope grade
- Pick how you know the slope: rise and run, percent grade, or angle.
- Type in the value or values you have.
- Read the percent grade, angle, 1:N ratio and slope length.
Examples
Rise and run to grade
rise = 10, run = 100
10% grade, 5.71 degrees, ratio 1:10, slope distance 100.5
Degrees to percent grade
angle = 30 degrees
57.74% grade, ratio about 1:1.73
Frequently asked questions
How do I convert percent grade to degrees?
Take the arctangent of the grade divided by 100. For a 10% grade that is atan(0.10), which is about 5.71 degrees.
What does a 1:N slope ratio mean?
It means 1 unit of vertical rise for every N units of horizontal run. A 1:10 ratio is a 10% grade, and a 1:50 ratio is a gentle 2% ramp.
Is percent grade the same as the angle in degrees?
No. Percent grade is rise over run times 100, while the angle is the arctangent of that ratio. They only match near zero and diverge as the slope steepens.
What is the slope distance?
It is the straight-line length measured along the slope, equal to the square root of rise squared plus run squared. It is shown only when you enter rise and run.
Why must the run be greater than zero?
Percent grade divides rise by run, so a run of zero would divide by zero and describe a vertical face rather than a slope. The calculator rejects that input.
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