Distance to Horizon Calculator
The horizon is the farthest point you can see on a flat surface. It depends on how high your eyes are, and it reaches farther the higher you stand.
- Free
- Works offline after your first visit
- Saves on this device
- No sign-up
- Updated
How it works
For eye height in metres, the distance to the horizon in kilometres is about 3.57 times the square root of that height. A second height, such as a tall object, is added in the same way, so the object can be seen from farther away.
This is the simple geometric figure. Air bends light a little, so the real view often runs somewhat farther than this.
Worked example
With your eyes 6 ft above the water, the horizon is 3 mi away.
Questions
Why can I see farther from a higher place?
The surface curves away, so a higher eye sees over more of the curve. Doubling your height does not double the distance; the distance grows with the square root of the height.
Does weather change the view?
Yes. Haze can hide the horizon well before this distance, and bending of light in the air can add a little range.
Can I use this to spot a ship?
It shows only the geometry. Whether a light or ship can be seen also depends on its size, brightness and the weather.
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