📏 Distance & Bearing Calculator
Click the start and end points on the map to instantly get the distance (Haversine great-circle) and bearing. Manual coordinate entry also supported.
🗺️ Measure by Clicking
🅰️ Click the start point
Presets:
✍️ Or enter coordinates manually
🅰️ Start
🅱️ End
📐 Method and accuracy
- Distance is the great-circle distance from the Haversine formula, using a mean Earth radius of 6,371,000 m.
- The bearing is the initial bearing at the start point: 0° is north, increasing clockwise. Over long distances the bearing keeps changing along the path.
- Haversine assumes a perfect sphere. The real Earth is an oblate ellipsoid (WGS84), which produces the differences below.
| Route | This tool (Haversine) | WGS84 ellipsoid (Vincenty) | Difference |
|---|---|---|---|
| Seoul City Hall ↔ Busan City Hall | 325.111 km | 324.915 km | 196 m (0.06%) |
| Seoul City Hall ↔ Jeju City Hall | 454.020 km | 453.039 km | 982 m (0.22%) |
| Seoul City Hall ↔ Incheon City Hall | 27.002 km | 27.043 km | 40 m (0.15%) |
This margin is fine for everyday use, but surveying or legal boundaries that need metre-level accuracy require an ellipsoidal geodesic calculation.