Rhumb line calculator (constant bearing)
Calculate the distance and constant bearing (rhumb line, or loxodrome) between two GPS coordinates — the route followed by holding a fixed heading from start to finish, unlike the great circle, which is the shortest path but requires continuously changing heading.
How it works
A rhumb line (or loxodrome) is a path that crosses all meridians at a constant angle — in other words, a route followed by holding a fixed compass heading, without ever correcting it. On a Mercator projection map, it appears as a straight line.
This is generally not the shortest path: the great circle gives a shorter distance but requires continuously changing heading. The rhumb line remains widely used in marine and air navigation because it is much simpler to follow: a single heading to hold for the whole crossing.
100% local processing: the calculation runs entirely in your browser via WebAssembly — your coordinates are never sent to a server.