Angle of Depression Calculator
Find the angle of depression from horizontal distance and height below eye level.
About Angle of Depression Calculator
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
Worked example
With the default values below, Angle of Depression Calculator returns Angle of Depression of 20.5560. Change any input above and every figure here is recalculated in your browser.
Inputs used
- Height below eye levelminimum 0
- 30
- Horizontal distanceminimum 0.001
- 80
Results
- Angle of Depression
- 20.5560 °
- Line-of-sight distance
- 85.4400
Step by step
- 1Apply arctan= 20.55604522°
- 2Line-of-sight distance= 85.44003745
Assumptions and limits
- The result is derived only from the 2 inputs listed above. Anything not among them is not part of the calculation.
- In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
- Figures are rounded for display to 4 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.
How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.
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.