Rhumb Line Calculator
Compute constant-bearing rhumb-line distance and heading between two coordinates.
About this tool
Calculate the rhumb-line (loxodrome) distance and the single constant bearing between two latitude/longitude points. Results are given in kilometres, statute miles and nautical miles, with the heading in degrees from true north. Built for navigators, route planners and anyone comparing constant-heading travel against the shorter great-circle path.
Frequently asked questions
What is a rhumb line?
A rhumb line (loxodrome) is a path of constant compass bearing. It plots as a straight line on a Mercator chart, which is why it is convenient for marine and air navigation, though it is slightly longer than the great-circle route.
How is the rhumb-line distance calculated?
Using the stretched-latitude method on a sphere of radius 6371 km: distance = sqrt(dLat^2 + q^2 * dLon^2) * R, where q = dLat/dPsi and dPsi is the difference of Mercator-projected latitudes.
How does it differ from great-circle distance?
The great-circle is the shortest path between two points but its heading changes continuously. A rhumb line keeps one bearing the whole way and is a little longer; the two converge near the equator and along meridians.