Great Circle Distance Calculator

The path follows a great circle - a circle whose center is the Earth's center.

A flat map stretches the Earth, and the stretching is worst near the poles — Greenland looks enormous on a Mercator map but is far smaller in reality. The great-circle path is the true shortest line on the sphere, and it often arcs toward the pole, which looks like a detour on a flat map. Trust the computed number, not your eyes on a rectangular map.

Haversine treats the Earth as a perfect sphere with a radius of 6,371 km, which makes results accurate to about 0.3% for most distances. The real Earth bulges slightly at the equator, so the most precise geodesy uses an ellipsoid model instead. For travel planning, education, and link budgets, 0.3% is more than good enough.

No, great-circle distance is the straight line over the Earth's surface and ignores roads entirely. Driving distance follows the road network and is almost always longer, sometimes dramatically so where mountains or water force detours. Use a routing service when you need road distance; use this tool for the theoretical minimum.

The great-circle distance is identical in both directions, but winds are not. Jet streams can push a plane along or hold it back, so eastbound flights across the Atlantic are routinely faster than westbound ones. Airlines also fly slightly different tracks each way for air-traffic reasons.

It uses the spherical Haversine model with a mean Earth radius of 6,371 km, not the more complex ellipsoidal Vincenty model. The difference is tiny — well under 1% — for nearly all practical purposes. If you need survey-grade geodesy, use a dedicated geodetic library rather than a web calculator.

Results are shown in kilometres and miles so you can read whichever you prefer. The underlying calculation is done in kilometres from the 6,371 km Earth radius and converted for display. Nautical miles matter in aviation and sailing, so convert from kilometres at 1.852 km per nautical mile when you need them.

Yes, Haversine works fine down to metres, though floating-point rounding makes it less ideal below a few dozen metres. For garden-scale measurements, a tape or a map measuring tool is more practical anyway. The formula shines at city-to-city and longer scales.

The calculation runs entirely in your browser with no server involved, so once the page has loaded it works even if your connection drops. No coordinates or queries are sent anywhere. That also means there is no usage limit or account involved.