Distance to Horizon Calculator

Your details

Choose a planet or moon to use its mean radius, or select Custom to enter your own.
Standard mode: enter your height, get the horizon distance. Reverse mode: enter a target distance, get the height required.
Your eye level or the elevation of any observation point above flat ground or sea level.
m
Enables the 7/6 standard refraction correction. Light bends slightly in the atmosphere, making the effective horizon about 7% farther than the pure geometric result.
Distance to horizonNear horizon
4.722

How far you can see to the horizon from your observation height

Distance unitkm
Effective radius used6,371
Radius unitkm
4.722 km
Eye level<5Hill top5-15High ground15-30Elevation30+

You can see 4.722 km to the horizon.

  • From 1.75 m on Earth you can see 4.722 km to the horizon.
  • This is the geometric result. Real-world visibility can be further extended by atmospheric refraction - toggle it on to see the difference.
  • At eye level (1.5-2 m), the horizon on Earth is only about 4-5 km away, a surprisingly short distance.

Next stepUse reverse-solve mode to find the height needed to spot an object at a specific distance, or try a different celestial body.

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