Calculate the initial and final bearing between two coordinates.
Bearing along a great circle changes continuously, so the initial and final bearings differ. On long east-west routes that change can exceed ninety degrees, which is why navigators recompute rather than hold a constant heading. The reverse bearing is not simply the initial bearing plus 180 degrees except on meridians and the equator, which is a common navigational trap.
Bearing Between Coordinates
Bearing = atan2(sin Δlon · cos lat₂, cos lat₁ sin lat₂ − sin lat₁ cos lat₂ cos Δlon)
Bearing = atan2(sin Δlon · cos lat₂, cos lat₁ sin lat₂ − sin lat₁ cos lat₂ cos Δlon) Bearing along a great circle changes continuously, so the initial and final bearings differ. On long east-west routes that change can exceed ninety degrees, which is why navigators recompute rather than hold a constant heading.
The reverse bearing is not simply the initial bearing plus 180 degrees except on meridians and the equator, which is a common navigational trap.
This calculator takes 4 inputs: First latitude, First longitude, Second latitude, Second longitude. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.