What this tool does
Computes the downward viewing angle from a height and a horizontal distance: the arctangent of height divided by distance, in degrees.
How to use it
- Enter the observer’s height.
- Enter the horizontal distance to the target in the same unit.
- Run it for the angle of depression in degrees.
Worked example
A height of 10 m over a horizontal distance of 20 m gives arctan(10/20) ≈ 26.57 degrees.
Calculation method
Depression angle
atan(height/distance)*180/piFrequently asked questions
- Is the distance a straight line?
- No, use the horizontal distance. Entering the slant distance gives too small an angle.
- Is the angle of elevation computed the same way?
- The value is identical — elevation and depression are alternate angles and equal in magnitude.
What this tool does not cover
Plane geometry only. Earth curvature, atmospheric refraction, and instrument error are not reflected.