Rhumb Line Course and Distance Calculator
Calculate rhumb line bearing and distance between two lat/lon coordinates.
Returns true course in degrees, distance in nm and km, and great circle comparison.
Rhumb Line (Loxodrome) A rhumb line crosses every meridian at the same angle — it is a constant compass course. On a Mercator chart, rhumb lines appear as straight lines.
Rhumb Line Bearing Δψ = ln(tan(π/4 + lat2/2) / tan(π/4 + lat1/2)) — the Mercator factor. θ = atan2(ΔL, Δψ) — the constant compass course.
Rhumb Line Distance d = √(Δφ² + q² × ΔL²) × R Where q = Δφ/Δψ (or cos(lat1) if nearly equal latitudes), R = 6371 km.
Rhumb vs Great Circle The great circle is the shortest path between two points on a sphere. The rhumb line is longer but navigationally simpler — constant heading, no course corrections needed.