Measuring grade on hills

Ron Gratz wrote:

Airstreamer67 wrote:
---My little gauge indicates my rig is at a 10-degree attitude while climbing my driveway. That's about a 11% grade. Pretty steep for me to walk.

A 10-degree slope is close to an 18% grade.
Hope that doesn't make it seem even steeper for you to walk. :)

The percent gradient for slopes from 1 to 10 degrees are given below:

Slope in degrees in column 1
Gradient in percentage in column 2

1 ____ 1.75%
2 ____ 3.49%
3 ____ 5.24%
4 ____ 6.99%
5 ____ 8.75%
6 ____ 10.51%
7 ____ 12.28%
8 ____ 14.05%
9 ____ 15.84%
10 ____ 17.63%


For small slopes, to convert degrees to gradient,

multiply slope, in degrees, by 100 times pi (3.1416) divided by 180

or, approximately 1.75% per degree.

The actual ratio increases as slope increases. At a slope of 45 degrees, which is a gradient of 100%, the ratio is 2.22% per degree.

Ron

Consider a right triangle with one leg horizontal and the other vertical. The hypotenuse is the road. The acute angle formed by the the hypotenuse and the horizontal leg is the angle of inclination. The tangent of that angle is the opposite (rise) over the adjacent (run). That is, the tangent of the angle is the slope of the road. To convert degrees to % grade, one can use a scientific calculator to computer the tangent of the degree measure (and multiply by 100.) To convert from % grade to degrees, one needs to calculate the inverse tangent of the % grade, written as a decimal number.

Tom