Geographic Midpoint Calculator
Find the exact geographic midpoint between two GPS coordinates. Returns the midpoint in all 7 coordinate formats. Accepts DD, DMS, DDM, UTM, MGRS, Geohash, or Plus Code.
The midpoint is calculated using spherical trigonometry, not simple coordinate averaging — so it correctly accounts for Earth's curvature. Simple averaging of lat/lng produces incorrect results for long-distance pairs.
Midpoint — All Formats
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Why Not Just Average the Coordinates?
Simply averaging latitude and longitude values gives an incorrect midpoint for long-distance pairs. The error grows with distance and is worst near the poles or when the two points span the antimeridian (±180° longitude).
The correct approach converts each point to a 3D Cartesian vector, averages the vectors, then converts the average back to lat/lng. This is equivalent to finding the midpoint of the great-circle arc connecting the two points.
Example: The midpoint between New York (40.71°N, 74.01°W) and London (51.51°N, 0.13°W) is approximately 53.5°N, 37.4°W — over the North Atlantic, south of Iceland. Simple averaging gives 46.1°N, 37.1°W — visually close but geographically off the great-circle route.
Spherical Midpoint Formula
Bx = cos(lat₂) × cos(Δlng) By = cos(lat₂) × sin(Δlng) lat_mid = atan2( sin(lat₁) + sin(lat₂), √((cos(lat₁)+Bx)² + By²) ) lng_mid = lng₁ + atan2(By, cos(lat₁)+Bx)
All angles in radians. Normalize lng_mid to [−180, 180].
Meeting Point Planning
Find the fair geographic midpoint for a meeting between people in two cities, then use the coordinate to find venues near that point.
Route Planning
Calculate the midpoint of a long route to plan rest stops, fuel stops, or overnight stays at the halfway point.
Surveying & GIS
Find the centroid between two reference points when establishing a new survey control point or splitting a large parcel.
Frequently Asked Questions
Is the midpoint the same as the halfway point along a route?
Yes — the geographic midpoint is the point that lies exactly halfway along the great-circle route connecting the two coordinates. It's the point where the distance to A equals the distance to B along that path.
What happens when the two points are antipodal?
Antipodal points (exactly opposite on the globe) have infinite midpoints — every great circle through one passes through the other, so no unique midpoint exists. The calculator will return an unpredictable result for near-antipodal pairs.
Can I use this to find the center of multiple points?
This calculator handles exactly two points. For the center of multiple points, convert each to Cartesian vectors (x = cos(lat)cos(lng), y = cos(lat)sin(lng), z = sin(lat)), average the vectors, and normalize the result back to lat/lng.