Angle of Depression Calculator
Find the angle of depression from horizontal distance and height below eye level.
Inputs
Vertical drop to the object.
Ground-level distance to the point below.
Angle of Depression
20.5560°
Line-of-sight distance
85.4400
Step by step
Apply arctan
arctan(height/distance) = arctan(30/80)
= 20.55604522°
Line-of-sight distance
√(30² + 80²)
= 85.44003745
How it works
The angle of depression is the angle between the horizontal and the line of sight looking downward to an object. It equals the angle of elevation measured from the object looking up to the observer (alternate interior angles).
Formula
Angle of Depression
θ = arctan(height / distance)
- h
- Height below eye level
- d
- Horizontal distance
Frequently Asked Questions
Is the angle of depression the same as the angle of elevation?
Yes — by alternate interior angles, the depression angle from the top equals the elevation angle from the bottom when measured with the same horizontal.
When is the angle of depression used?
Looking down from a cliff, a building, or an aircraft to a ground target. It is common in surveying, aviation, and architecture.