Observer height (metric): (imperial):
Distance to object (metric): km (imperial): miles
Coefficient of refraction:
Click Enter, the C-key or the Calculate button to calculate the hidden heigh.
To calculate the radius of the Earth from a measured hidden hight,
go to the end of the page and enter the hidden height.
| Distance to the horizon: | km | miles |
| Distance from the horizon to the object: | km | miles |
| Distance along the sea to the object: | km | miles |
| Earth radius: | km | miles |
| Earth calculated radius: | km | miles |
| Percentage error: | % | |
| Apparent radius: | km | miles |
| Hidden hight: | m | ft |
| Dip angle: | degrees | |
| Calculated coef. of refraction: |
Measured hidden height (metric): m (imperial): ft
Click Enter (or the R-key) to calculate radius and Coefficient of refraction