Piloting

Distance to horizon

How far away the horizon is from a given eye height, and how far off a lighthouse or object of known height first becomes visible.

Inputs

Units

Your eye / antenna height

Object height (optional, e.g. a light)

Result

Distance to horizon (from you)—

Distance to horizon (from object)—

Total sighting range—

Uses the standard geometric horizon formula with normal atmospheric refraction (d = 1.17 × √height in feet). Actual visibility also depends on light intensity, atmospheric clarity, and observer height accuracy.