Midpoint Calculator
Find the great-circle halfway point between two coordinates. Uses the accurate 3D-vector method, not naive lat/lng averaging. Free, with a map.
When to use the great-circle midpoint
- Choosing a meeting point halfway between two cities.
- Placing a marker at the visual centre of a route segment.
- Splitting a long flight path into equal halves.
- Approximating a centre point for a 2-point bounding region.
Frequently Asked Questions
How is the midpoint between two coordinates calculated?
This tool computes the great-circle midpoint — the point on the shortest path between the two coordinates that is equidistant from both. It converts each endpoint to a 3D Cartesian vector on a unit sphere, averages them, and projects the result back to lat/long. This is more accurate than simply averaging latitudes and longitudes, which breaks down for points far apart or near the poles.
Why is averaging lat/lng directly wrong?
For two points at the same longitude it works fine, but for points spanning a large longitude range (e.g. Tokyo and New York) the arithmetic mean lands in the wrong place because the meridians converge toward the poles. The 3D-vector average handles this correctly and always lands on the true great-circle path.
What about the midpoint of more than two points?
That's called the centroid, and it's a separate tool: Centroid Calculator. The midpoint specifically refers to the halfway point of exactly two coordinates.
Is the midpoint always between the two points?
Yes, on the shorter of the two great-circle arcs. For antipodal points (exactly opposite sides of the Earth) every point on every great circle through them is equidistant, so the midpoint is undefined — the tool will warn you in this rare case.