Distance calculator
Calculate a local WGS84 spherical great-circle distance between two coordinates.
How it works & useful details
How it works & limits
Uses the haversine formula with the WGS84 mean Earth radius of 6,371.0088 km. It reports a spherical great-circle distance, which is useful for planning and comparison.
It does not account for routes, terrain, ellipsoidal geodesics, local projection distortion or travel restrictions.
Private local calculation
Coordinates and pasted data stay in this browser tab. These tools use no map tiles, geocoding, routing, elevation data or network requests.
About this tool
Distance calculator measures the great-circle distance between two WGS84 coordinates using the spherical haversine formula. It is a dependable estimate for straight-line distances in navigation and geographic analysis.
The calculation runs locally without map tiles, elevation data, or routing services, so it works the same offline. Distances are reported in the units you choose.
How to use it
- Enter the two coordinates in decimal degrees.
- Choose the output unit.
- Read the great-circle distance.
- Compare coordinates by editing the inputs.
Worked example
London (51.5074, −0.1278) to New York (40.7128, −74.006) is 5,570.23 km, 3,461.18 statute miles, or 3,007.68 nautical miles along a great circle. The central angle between the two points is 50.09°. Multiplied by the mean Earth radius of 6,371.0088 km, that gives the distance.
The haversine formula is used because it stays numerically stable for very short distances, where simpler formulas lose precision.
Straight-line distance vs. travel distance
Great-circle distance is the shortest path over the Earth's surface, the "as the crow flies" figure. Flights come close to it, but roads, railways, and shipping lanes are longer, often by 20–40% on land. Use this number for comparisons, radius searches, and sanity checks, and use a routing service for travel planning.
The spherical model differs from the more precise ellipsoidal (Vincenty or Karney) distance by up to about 0.5%. Across London to New York, that is up to roughly 20–25 km. For property boundaries or surveying, use ellipsoidal geodesic software.
Frequently asked questions
Is this the same as travel distance?
No. It is the straight-line distance over the sphere; roads and terrain make real travel longer.
How accurate is the spherical model?
It is typically within a few tenths of a percent for common distances, since the Earth is slightly flattened rather than a perfect sphere.
Is any coordinate sent to a server?
No. Distances are computed in the page and no network request is made.
What coordinate format do I need?
Decimal degrees in WGS84, the format used by GPS and web maps. Use the coordinate converter first if your source is in degrees, minutes, and seconds.