The grade percentage is calculated by dividing the rise over run and by multiplying the result by 100 percent. In other words, the change in vertical distance divided by the change in horizontal distance times 100 percent gives the grade percentage.
When calculating elevation grade percentage, it is important to ensure that vertical distance and horizontal distance are measured in the same units. For example, if an incline rose 10 meters vertically over 100 meters of horizontal distance, then its grade percentage would be (10 meters/100 meters)*100% = 10 percent grade. If, for example, vertical change is measured in meters and horizontal change is measured in kilometers, then horizontal change should be converted to meters before making the calculation.