Compass Bearing Converter Formula

Understand the math behind the compass bearing converter. Each variable explained with a worked example.

Use the Compass Bearing Converter

Formulas Used

Cardinal Direction

main_direction = value < 22.5 ? 1 : (value < 67.5 ? 2 : (value < 112.5 ? 3 : (value < 157.5 ? 4 : (value < 202.5 ? 5 : (value < 247.5 ? 6 : (value < 292.5 ? 7 : (value < 337.5 ? 8 : 1)))))))

Radians

radians = value * pi / 180

NATO Mils

mil_nato = value * 17.7778

Variables

VariableDescriptionDefault
valueBearing (degrees from North)(°)135

How It Works

Compass Bearings

Cardinal Directions and Degrees

| Bearing | Direction | |---|---| | 0° (360°) | North (N) | | 45° | Northeast (NE) | | 90° | East (E) | | 135° | Southeast (SE) | | 180° | South (S) | | 225° | Southwest (SW) | | 270° | West (W) | | 315° | Northwest (NW) |

Bearings are measured clockwise from true North. Output values: 1=N, 2=NE, 3=E, 4=SE, 5=S, 6=SW, 7=W, 8=NW.

Worked Example

Convert 135° bearing.

value = 135
  1. 01135° falls between 112.5° and 157.5°
  2. 02Direction: Southeast (SE)
  3. 03NATO mils = 135 x 17.78 = 2,400 mils

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