GPS distance calculator — between two coordinates

What this calculator does

The tool above takes two points and returns the shortest distance between them over Earth’s surface, the kind of distance an airline quotes when it tells you the flight is 5,000 km, not the longer driving distance that follows roads. It calculates on the WGS 84 ellipsoid using Vincenty’s formulae, published in 1975 and widely used in survey and mapping software, and shows:

• the distance in kilometers, statute miles, nautical miles, and meters
• the initial bearing leaving A and the final bearing arriving at B
• the midpoint of the route
• the spherical haversine distance for comparison, and the difference
• the great-circle route on a map

Need the coordinates first? The My Location tool gives you yours in two seconds. To see the same point in every format, use the Coordinates Converter. To pick two points visually instead of typing them, drop pins on the interactive map and read off the coordinates.

Enter latitude and longitude in any format

Each point box reads the same formats as our coordinate converter, and shows underneath how it understood your input:

• Decimal degrees: 51.5074, -0.1278 or 51.5074° N, 0.1278° W
• DMS: 51°30'26.6"N 0°07'40.1"W
• DDM: 51°30.444'N 0°07.668'W
• UTM: 30U 699316 5710164
• A Google Maps link containing @lat,lon

You can mix formats: a DMS point A and a UTM point B work fine. Out-of-range values are flagged instead of producing a wrong distance.

Sanity-check the math against known distances

The first time you use any distance calculator, it pays to verify it against pairs you already know. These six city pairs are calculated with the calculator’s own code when the page is built, so pasting any pair into the tool gives exactly these numbers. The last two columns show what a spherical haversine calculator would say instead, and how far off that is.

Distances are rounded to the nearest whole unit. Checked against the GeographicLib reference library in October 2026.

How accurate is great-circle distance, really?

Earth is not a perfect sphere. Its spin makes it bulge at the equator: the equatorial radius is about 21 km larger than the polar radius. The haversine formula, which most online distance calculators use, ignores that and treats Earth as a ball with a 6,371 km radius. This calculator instead uses the WGS 84 ellipsoid, the model GPS itself uses, so the bulge is accounted for.

We tested the calculator against GeographicLib, the reference library used in GIS software, on 20,000 random pairs of points around the world. The largest difference was under 0.1 mm. In practice your input is the limit: six decimal places pin each point to about 11 cm.

Haversine vs ellipsoid: when the difference matters

The spherical haversine shortcut is wrong by up to about 0.56%, and the error depends on direction and latitude. It is worst for short north–south trips near the equator, where it overstates distance by up to about 0.56%, and for short trips near the poles, where it understates by up to about 0.44%. Over very long routes the errors partly cancel; from the equator to the North Pole it is only about 0.06% off.

In kilometers, the table above shows it plainly: haversine is about 15 km short on New York to London and about 32 km long on Cape Town to Cairo. That is irrelevant for estimating a flight time and very relevant for fuel planning, surveying, or checking a developer’s own distance code. The “sphere” line in the tool shows the gap for whatever two points you enter.

Why driving distance is always longer

People sometimes punch in two coordinates expecting the driving distance and are surprised when the result is much smaller. Driving distance has to follow roads, go around lakes and mountains, respect one-way streets, and divert through interchanges. A drive from London to Paris is about 460 km along roads, but only about 344 km in a straight line over the English Channel. The straight-line version is the one this page calculates.

If what you actually want is the road distance, use the Driving Directions tool instead. It calls the routing engine that does know about roads. Across the US, roads average about 1.4 times the straight-line distance.

What the bearing field tells you

The calculator returns two bearings. The initial bearing is the compass direction you set off in from point A; the final bearing is the direction you are travelling when you arrive at point B. On the shortest route the two are usually different, because a great circle crosses each meridian at a different angle. London to Tokyo leaves London heading about 32° (north-northeast) and arrives in Tokyo heading about 156° (south-southeast), even though Tokyo is south of London on the map.

The midpoint between two coordinates

The midpoint is the place exactly halfway along the shortest route, and it is shown as an orange dot on the map. It is not the average of the two latitudes and longitudes: averaging New York and Sydney gives 3.4°N, 38.6°E, in East Africa near the Ethiopia–Kenya border, while the real halfway point is in the central Pacific, near 8.9°N, 147.7°W. The tool walks half the route’s length along the ellipsoid from point A to find it.

Reading the great-circle line on the map

The blue line is the actual shortest route. On a flat web map it usually looks curved, bowing toward the nearer pole, because the map stretches the globe sideways. That curve is the straight line on the real planet. Routes that cross the 180° meridian, such as Tokyo to Los Angeles, are drawn across the Pacific rather than the long way round the map.

Frequently asked questions

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