The steepness of a hill is called the gradient, also known as slope and grade. Knowing the gradient of a hill can be useful. For example, cyclists often measure the gradient of hills on their routes in order to determine which gears their bike needs to have, or how much effort it is going to take to complete a hilly route. The easiest way to find the gradient of a hill is to use a simple formula called "rise over run."
Find a location on the hill that is representative of the general slope. For example, avoid choosing a location that has a small hump or valley. The goal is to choose a location that is smooth and will provide a good idea of the grade of the rest of the hill.
Place the level on the hill so that one end is pointing upwards, the other downwards.
Lift the downward end up so that the little bubbles inside the level move in between the two marked lines. When the bubble stays between the lines, the level is level.
Use the ruler to measure the distance between the bottom of the lifted end of the level and the surface of the hill.
Use the ruler to measure the exact length of the level.
Divide the result from Step 4, the height of the lifted end of the level, by the result from Step 5, the length of the level. For example, if the height of the level was 5 cm (2 inches), and the length of the level was 45 cm (18 inches), your result would be 0.111.
Multiply your result by 100. This converts it to a percentage, which is how gradients are reported. For example, if your result was 0.111, you would multiply that by 100 to get 11.1 per cent. Then round off the last digit for a final result of an 11 per cent gradient.