Wanderlust World Wanderlust World The distance to the horizon over the ocean is determined by your eye height above sea level and Earth's curvature. The geometric formula (ignoring atmospheric refraction):
d (km) = 3.57 × √h (meters)
d (miles) = 1.22 × √h (feet)
| Vantage Point | Eye Height | Horizon Distance |
|---|---|---|
| Standing at sea level | 1.7 m (5.6 ft) | 4.7 km (2.9 mi) |
| Small boat cockpit | 3 m (10 ft) | 6.2 km (3.8 mi) |
| Ship's bridge (container ship) | 30 m (100 ft) | 19.6 km (12.2 mi) |
| Cliff top | 100 m (330 ft) | 35.7 km (22.2 mi) |
| Airliner cruising | 10,000 m (33,000 ft) | 357 km (222 mi) |
Standard atmospheric refraction bends light downward, extending the visible horizon by ~8%. Multiply distances above by 1.08 for real-world values.
So from a beach, you see ~5 km; from a cruise ship deck, ~21 km; from a plane, ~385 km. The ocean's "edge" is always a function of your height.