What is the haversine formula — distance by coordinates

The haversine formula computes the great-circle distance between two points on a sphere from their latitude and longitude. It gives the “as-the-crow-flies” distance — the shortest path on the Earth's surface, not a road route.

The accuracy is sufficient for the vast majority of tasks: city and intercity distances, flight estimates, and geolocation. Measurements that require the ellipsoidal shape of the Earth use more complex models.

The ToolsHelper distance calculator uses haversine: enter two points or pick cities to get the distance in kilometers or miles, bearing, and a flight time estimate. Terrain and the road network are not taken into account.

The haversine formula treats the Earth as a sphere and returns the great-circle distance between two latitudes and longitudes. It is not a driving route: roads, ferries, and borders are ignored. Mean radius is about 6371 km, so a small change in radius moves a long flight by a few kilometres. Antipodes are about 20000 km. This page names the formula. The distance tool runs it on the coordinates you type.