How do you figure out slope of a grade in percent?

Answer 1

1. Determine the height difference (a) between the start and end of the slope by subtracting the starting height from the final height (if it is a downhill slope the difference will be a negative number).
2. Determine the horizontal distance (b) between the starting point and the final point. If you only know the actual linear distance (c) along the slope, you can figure the horizontal distance using the Pythagorean Theorem: a2+b2=c2. For example, if the linear distance (c) along the slope from start to finish is 1000 feet, and the height difference (a) is 75 feet, then using the theorem you would have 752+b2=10002 or 5625+b2=1000000. Your horizontal distance (b) would therefore be b2=994375 or b=997.2 feet
3. Divide the height difference (a) by the horizontal distance (b) and multiply by 100. This gives you the grade of the slope in percent. In the example it would be 75 ÷ 997.2 × 100 = 7.5% grade