An clinometer (or inclinometer) is an instrument for measuring angles of slope, elevation or depression.

Students can make a type of clinometer by taping together a protractor and a thin tube (such as a straw) to look through. A string with a weight must be attached to more accurately read the measure of the angle from the protractor.

Since a protractor is used in the construction of the clinometer, the angle measure read from the protractor must be subtracted from 90°.