Coordinate Midpoint Calculator
The coordinate midpoint calculator finds the geographic midpoint between two latitude/longitude coordinates. It uses the spherical 3D vector method: converting each point to a unit vector in 3D space, averaging the vectors, and converting back to latitude and longitude. This is more accurate than simply averaging the coordinates, especially for points that are far apart or straddle the antimeridian. Enter both points in decimal degrees and the calculator returns the midpoint latitude, longitude, and the great-circle distance from each input point to the midpoint.
Point 1
Point 2
Geographic midpoint formula
Convert to Cartesian: x = cos(lat)*cos(lon), y = cos(lat)*sin(lon), z = sin(lat)
Average: xm = (x1+x2)/2, ym = (y1+y2)/2, zm = (z1+z2)/2
Convert back: lat_mid = atan2(zm, sqrt(xm^2+ym^2))
lon_mid = atan2(ym, xm)
This method gives the correct great-circle midpoint for any pair of locations on Earth and handles the antimeridian correctly.
Use cases for geographic midpoints
- Finding a fair meeting point equidistant from two locations.
- Identifying the center of a geographic region or route.
- Centering a map view between two points of interest.
- Computing the approximate geographic center of a bounding box for GIS display.
- Interpolating intermediate waypoints along a flight or navigation route.
Coordinate midpoint calculator: frequently asked questions
What is the geographic midpoint?
The geographic midpoint is the point on the surface of the Earth that is equidistant from two other points along the great-circle arc. It is also called the great-circle midpoint or geographic center. It is not the same as the arithmetic average of the latitudes and longitudes for points far apart.
Why not just average the latitudes and longitudes?
Simple arithmetic averaging of lat/lon works reasonably well for points close together, but gives incorrect results for points far apart, especially across the antimeridian (180 degree longitude) or near the poles. The spherical 3D midpoint method is accurate for any two points on Earth.
How is the geographic midpoint calculated?
Convert both lat/lon points to 3D Cartesian coordinates (x, y, z) on the unit sphere. Add the two vectors, then normalize back to a unit vector. Convert the result back to latitude and longitude. This gives the correct spherical midpoint.
What is the midpoint useful for?
The geographic midpoint is useful for finding the center of a route or region, identifying a meeting point between two locations, GIS analysis, and calculating the centroid of geographic features. It is also used in geospatial data processing to represent the average location of a set of coordinates.
Can this calculator find the midpoint of more than two points?
This calculator finds the midpoint between exactly two points. For more than two points, sum all the Cartesian vectors, normalize, and convert back to lat/lon. This gives the geographic center of mass of the point set.
Official sources
- USGS: USGS coordinate distance reference.
- NOAA National Geodetic Survey: NGS geodetic tools and coordinate systems.
Reviewed by the CalculatorHub team, edited by James Graham, 15 June 2026. See our methodology.