GPS Distance Calculator
Calculate the great-circle distance between two GPS coordinates. Accepts any format — DD, DMS, DDM, UTM, MGRS, Geohash, or Plus Code.
Great-circle distance is the shortest path between two points on Earth's surface, calculated using the Haversine formula. Results are shown in kilometers, miles, and nautical miles.
Great-Circle Distance
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Kilometers
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Miles
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Nautical Miles
How the Haversine Formula Works
The Haversine formula calculates the shortest distance between two points on a sphere — the great-circle distance. It accounts for the curvature of Earth using the WGS84 mean radius of 6,371 km.
Unlike a straight line through the Earth (chord distance), great-circle distance is the actual surface distance you'd travel. A plane flying New York to London follows a great-circle route, which arcs far north over Greenland rather than going straight across the map.
Accuracy: Results are accurate to within about 0.3% for most locations. Extreme precision calculations (surveying, geodesy) should use the Vincenty formula, which accounts for Earth's flattening.
The Formula
a = sin²(Δlat/2) + cos(lat₁)
× cos(lat₂) × sin²(Δlng/2)
c = 2 × atan2(√a, √(1−a))
d = R × c
(R = 6,371 km)
All angles in radians. Δlat and Δlng are the differences between the two points.
Pilots & Aviation
Flight planning, fuel stop calculations, range checks. Nautical miles are the standard aviation distance unit.
Sailors & Marines
Route planning, passage distances. Nautical miles match chart scales directly.
Hikers & Outdoors
Trail planning, campsite distances, emergency egress routes. Use km or miles to match your map.
Frequently Asked Questions
What is the difference between great-circle distance and straight-line distance?
Great-circle distance follows the surface of the Earth — it's the shortest path you can fly or sail. Straight-line (chord) distance cuts through the Earth itself. For most practical purposes (navigation, route planning) you want great-circle distance.
Why is the distance different from what Google Maps shows?
Google Maps shows driving or walking distance along roads, which is always longer than the straight-line great-circle distance. This calculator shows the shortest possible surface distance (as the crow flies).
What is a nautical mile?
One nautical mile equals exactly 1,852 meters (1.852 km or 1.151 statute miles). It is defined as one arcminute of latitude along any meridian. Pilots and sailors use nautical miles because they relate directly to latitude on charts.
How accurate is this calculator?
The Haversine formula is accurate to within 0.3% for points up to ~20,000 km apart. For geodetic surveying precision, the Vincenty formula (which accounts for Earth's ellipsoidal shape) is preferred.