How to Calculate Distance Between Latitude and Longitude Coordinates

 

Latitude and longitude identify a position on Earth using angles rather than ordinary distances on a flat grid. To estimate the separation between two positions, you need a model of Earth's surface. A great-circle calculation treats Earth as a sphere and measures the shorter surface arc connecting the coordinates.

The Latitude Longitude Distance Calculator reports this distance in kilometers, miles and nautical miles. It also shows the central angle between the positions. The result is an estimate of surface distance, not a driving route or a straight chord through Earth.

Enter latitude and longitude in decimal degrees

Latitude ranges from -90 degrees at the South Pole to 90 degrees at the North Pole. Longitude ranges from -180 to 180 degrees. North and east use positive values; south and west use negative values. Keep latitude and longitude in the correct fields rather than treating their order as interchangeable.

For example, a latitude of 40.7128 and longitude of -74.0060 describe a position north of the equator and west of the prime meridian. This calculator accepts signed decimal degrees. Convert degrees-minutes-seconds coordinates before entering them; place names and addresses are not accepted.

Understand the great-circle model

A great circle passes through the center of a sphere. The shorter arc between two surface points is the shortest surface path on that sphere. Multiplying the central angle in radians by the sphere's radius gives the arc length: distance = radius x central angle.

The calculator uses a mean Earth radius of 6371.0088 km. It derives the angle from the coordinate directions using an atan2 formula. This avoids relying solely on inverse cosine, which can lose precision for positions that are very close together.

Work through one degree at the equator

Enter Latitude 1 (degrees) 0, Longitude 1 (degrees) 0, Latitude 2 (degrees) 0 and Longitude 2 (degrees) 1. Select Calculate distance.

The central angle is 1 degree, or pi / 180 radians. Multiplying by 6371.0088 gives approximately 111.195080 kilometers. Dividing kilometers by 1.609344 gives 69.093420 miles. Dividing kilometers by 1.852 gives 60.040540 nautical miles, with all displayed figures rounded.

That kilometers-per-degree value applies to this equatorial example. Longitude lines converge toward the poles, so a one-degree longitude difference does not represent a fixed distance everywhere on Earth.

Handle the date line and poles

Positions at (0, 179) and (0, -179) are close across the international date line. The shorter equatorial arc spans 2 degrees, giving approximately 222.390160 km. Using the raw longitude difference as a 358-degree journey would describe the long way around.

Longitudes -180 and 180 identify the same meridian. At a pole, every longitude identifies the same position. Identical positions return zero distance. Exact opposite points are half a spherical circumference apart, approximately 20015.114442 km on this model. Their distance is defined even though there is no unique great-circle route between them.

Distinguish distance from route length

Roads, paths, bridges and restricted areas affect real journeys. A great-circle result cannot tell you the length of a driving route or how long a trip will take. Terrain and elevation are also excluded. Use a routing service when you need travel directions or road distance.

Earth is not a perfect sphere. An ellipsoidal geodesic calculation can give a different result, with spherical errors reaching roughly half a percent depending on the positions. Extra decimal places do not correct this model difference or improve inaccurate source coordinates.

Choose the right coordinate calculator

Use this tool for geographic latitude and longitude. For x and y coordinates on a flat Cartesian grid, use the Distance Between Two Points Calculator. Applying flat-grid formulas directly to latitude and longitude degrees generally produces misleading results.

The geographic tool runs locally without requesting your location or map data. Its estimates are useful for comparison and learning, but do not replace surveying or navigation equipment.