Great-circle Distance and Bearing Calculator

How to use Great-circle Distance and Bearing Calculator

Stable spherical atan2 arithmetic combines the sine and cosine of the short central angle. Multiply by the entered sphere radius; tangent components give the initial bearing.

1. Enter first latitude (degrees), first longitude (degrees), second latitude (degrees), second longitude (degrees), sphere radius (distance units).
2. Check the model, units, and supported limits before calculating.
3. Run the tool, inspect the result, then copy or download it.

Good to know

• Latitude ±90°, longitude ±180°, positive radius. Spherical approximation, not road distance or certified navigation. Coincident, antipodal, or starting-pole initial bearings are undefined.
• Runs locally. Numeric inputs are bounded; floating-point output is approximate and rounded to 12 significant digits. Unsupported or non-finite calculations produce an error.