Compass Bearing Converter

A compass bearing is measured in degrees clockwise from North.

Main cardinal directions (4):

• N = 0° (or 360°)
• E = 90°
• S = 180°
• W = 270°

Intercardinal directions (4 more):

• NE = 45°, SE = 135°, SW = 225°, NW = 315°

All 16 compass points (22.5° apart):

Formula: Each of the 16 points covers a 22.5° arc. Direction index = round(degrees / 22.5) mod 16

The full 32-point rose

Traditional compass roses go one step finer, splitting each 16-point arc in half to give 32 points 11.25° apart. The extra points are named “by”, as in “north by east” for the point just east of due north. You will still see these on old charts and in sailing directions.

The converter names both. The 16-point name is the one you would use out loud; the 32-point name is there because you will meet it on old charts and in sailing directions, and it is otherwise hard to look up.

Bearings always run clockwise from north and are written as three digits (045°, not 45°) so they can’t be mistaken for anything else over a radio or on a chart. That three-digit habit comes straight from navigation and aviation, where ambiguity is genuinely dangerous.

Two ideas go hand in hand with bearings. The first is the back bearing, the reverse direction, found by adding or subtracting 180°: if you walk out on a bearing of 060°, your route home is 240°. The second is the difference between true and magnetic north. A compass points to magnetic north, but maps are drawn to true north, and the gap between them (magnetic declination) can run to many degrees depending on where you are. For a casual stroll it rarely matters, but over a long distance an uncorrected bearing will steadily walk you off course.