Slope Percentage Calculator

What Is Slope Percentage?

Slope percentage (also called grade or gradient) expresses how steep a line, road, or ramp is as a percent of horizontal distance. It is the rise divided by the run, multiplied by 100. A 5% slope means the surface rises 5 units for every 100 units of horizontal travel.

Engineers, surveyors, cyclists, and math students all use slope percentage. You can also convert between slope percentage and angle in degrees using tangent. For related tools, see our Slope Calculator and Elevation Grade Calculator.

Slope Percentage Formula

$$\\text{slope \\%} = \\frac{\\text{rise}}{\\text{run}} \\times 100$$

To convert from angle $\\theta$ in degrees:

$$\\text{slope \\%} = \\tan(\\theta) \\times 100$$

To convert from slope percentage $s$ back to degrees:

$$\\theta = \\arctan\\left(\\frac{s}{100}\\right)$$

Worked Example

A ramp rises 1 m over a horizontal run of 20 m. The slope is $1/20 = 0.05$, so the slope percentage is $0.05 \\times 100 = 5\\%$. The angle is $\\arctan(0.05) \\approx 2.86°$.