Angle of Depression Calculator
Find the downward angle from a horizontal eye line to a lower target.
Formula
Angle = atan(vertical drop / horizontal distance); sight = √(drop²+distance²).
Vertical drop to target: 100 ft · Horizontal distance: 100 ft · Angle of depression ≈ atan((100 ft × 0.3048 m/ft)÷(100 ft × 0.3048 m/ft))×180÷pi · Line-of-sight distance ≈ sqrt((100 ft × 0.3048 m/ft)^2+(100 ft × 0.3048 m/ft)^2)
How to use
- Enter vertical drop from eye level to the target.
- Enter horizontal distance to the target.
- Read the angle and line-of-sight distance.
Examples
- A 3 m drop and 4 m horizontal distance give 36.870°.
Frequently asked questions
Which height should I enter?
The difference between observer eye height and target height.
Is the angle measured from vertical?
No. It is measured downward from horizontal.
Is this suitable for long-range surveying?
It assumes a flat right triangle; curvature and atmospheric refraction are excluded.
Sources
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