Measure the height of an object using the %-scale.

1. Place yourself at a suitable distance from the object. For example 10 metres.

2. Hold the clinometer vertically close to one of your eyes.

3. Sight with both eyes towards the top of the object.

4. Read the angle/height at the index line. Because of the optical illusion, the index line will appear to "stand out" from the clinometers housing making it easy to very accurately read the correct angle. For example 70%.

5. Remember to add the angle/height below the horizontal line to the first reading, in order to obtain the correct height of the object. For example 15%.

6. In this example the correct height of the object would be 70%+15%=85% x 10 metres = 8.5 metres.