Compass Bearing Calculator

How it is calculated

The tool gives the initial great-circle bearing from point 1 to point 2, plus the distance. With latitudes φ and longitudes λ in decimal degrees (north and east positive), and Δλ = λ₂ − λ₁: y = sin Δλ · cos φ₂, x = cos φ₁ · sin φ₂ − sin φ₁ · cos φ₂ · cos Δλ, and bearing = atan2(y, x) normalised to 0–360° clockwise from true north. The result is also named as one of 16 compass points (N, NNE, NE and so on), each 22.5° wide. Distance uses the haversine formula on a spherical Earth of radius 6371 km, shown in kilometres. Because the Earth is treated as a sphere, distances can be off by a fraction of a percent.

Common mistakes

• Entering south latitudes or west longitudes as positive numbers. West and south need a minus sign.
• Swapping latitude and longitude. The order is latitude first, then longitude, for each point.
• Expecting one constant heading for the whole trip. This is the initial bearing; on a long great-circle route the heading changes along the way.
• Entering degrees, minutes and seconds in the decimal field. Convert them to decimal degrees first.
• Confusing true north with magnetic north. The bearing is measured from true north, so a compass needs the local magnetic declination applied.