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How to calculate a slope gradient

Updated June 18, 2018

Slope and gradient are two ways to express the steepness of a hill or ramp. Knowing the slope is important when constructing handicap ramps because if the ramp is too steep, it will be very difficult or even impossible for people in wheelchairs to climb the ramp. Similarly, if a hill is too steep, a car may have great difficulty getting up or down the slope, especially in poor weather conditions.

Measure the distance the hill or ramp covers. For example, if you are measuring the slope of a wheelchair ramp, you would measure the distance from where the ramp starts to where the ramp ends. If you are using a hill, you can use a map scale to find the distance covered.

Measure the change in height of the ramp or hill. With a ramp, you can measure the distance from the ground straight up to the top of the ramp. With a hill, you can use a topographic map and find the beginning and ending heights. Use the difference between them as the elevation change.

Divide the change in elevation by the distance over which the elevation change takes place. For example, you had a ramp that went up by 10 feet over a distance of 40 feet, you would divide 10 feet by 40 feet to find the slope equals 0.25.

Multiply the slope by 100 to find the per cent gradient. In this example, you would multiply 0.25 by 100 to find the gradient to be 25 per cent.

Things You'll Need

• Tape measure
• Topographic map