How distance is calculated
whatdistance measures the shortest distance over Earth’s reference surface. It is an as-the-crow-flies calculation, rather than a driving or walking route. It does not include terrain or elevation.
Frequently asked questions
Coordinates and what3words
Choose decimal degrees (DD), degrees and decimal minutes (DDM), degrees/minutes/seconds (DMS), or a what3words address independently for each point. Enter latitude before longitude, or tick Reverse coordinate order to enter longitude first. For DDM and DMS, include N/S and E/W hemispheres. what3words inputs require your own API key and use the centres of their squares.
Geodesic or Haversine?
The recommended geodesic method accounts for Earth’s slightly flattened shape using the WGS 84 ellipsoid and Karney’s algorithm. Choose the Haversine tab after calculating to see the distance on a sphere instead. Differences depend on location and direction.
How accurate is the result?
The calculation retains full numerical precision, but the real-world accuracy depends on your input locations. Rounded coordinates, GPS uncertainty and a what3words square’s extent still matter. More decimal places do not make a location more accurate.
Are my locations saved?
Locations and your API key are sent in a request to calculate the distance. They are not placed in the page URL or saved by this tool. Keep the page open to retain your key in memory, or use Clear key to remove it.