Earth Curve Calculator

Enter your height above sea level and optionally the target height to compute horizon distance and hidden height.

Observer Height (m)

Target Height (m) (optional)

Distance (km) (optional)

Results

Distance to Horizon: - km

Hidden Height: - m

Drop per km: - m

Formula: Horizon distance = 3.57 * sqrt(observer height in meters) km. Hidden height = (distance^2 * 1000) / (2 * R) - target height, where R = 6371 km. Drop per km = (1000^2)/(2*6371000) m ≈ 0.0785 m per km.