Flight Mileage Calculator
Enter the latitude and longitude of two points to find the great-circle distance between them.
Use decimal degrees (positive for North/East, negative for South/West).
How great-circle distance is calculated
This calculator uses the haversine formula to find the great-circle distance — the shortest path between two points along the surface of a sphere, which is how commercial flights actually route over the curved Earth rather than following a straight line on a flat map.
The formula converts the latitude and longitude of both points to radians, then calculates the central angle between them using trigonometric functions, finally multiplying by Earth's radius to get the distance.
Frequently asked questions
Why is the great-circle distance shorter than it looks on a map?
Flat maps distort the true shape of the Earth's surface. A straight line on a flat map (a Mercator projection, for example) is usually not the shortest actual path between two points — the true shortest path curves toward the poles, which is why long flights often appear to arc on a map.
Does this match the actual distance a flight travels?
It's close but not exact — actual flight paths deviate from the pure great-circle route due to air traffic routes, weather avoidance, wind patterns, and airspace restrictions, so real flown distance is typically slightly longer than the great-circle distance.
Where do I find an airport's latitude and longitude?
Airport coordinate data is publicly available from aviation databases and mapping services — search for the airport's ICAO or IATA code along with "coordinates" to find its published latitude and longitude.