Math
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Great Circle Calculator.
Calculate spherical great-circle distance with the haversine formula.
Set your values
Results update as you type.
Use Cases
Navigation and Travel Planning
Determine the shortest flight path or sailing route between two cities, useful for estimating travel time and fuel consumption.
Example: Calculate the distance between New York (40.7128° N, 74.0060° W) and London (51.5074° N, 0.1278° W).
Geographic Research and Education
Help students and researchers understand spherical geometry and the concept of great circles, which are the basis for many map projections.
Example: Find the distance between the North Pole (90° N, 0° E) and the equator (0° N, 0° E).
Frequently Asked Questions
- What is the great-circle distance?
- The great-circle distance is the shortest distance between two points on the surface of a sphere, measured along the surface. It is calculated using the haversine formula, which accounts for the spherical shape of the Earth.
- How do I use this calculator?
- Enter the latitude and longitude of the two points in degrees, and the sphere radius in kilometers. The calculator will output the great-circle distance in kilometers.
- What is the haversine formula?
- The haversine formula is an equation that calculates the great-circle distance between two points on a sphere given their longitudes and latitudes. It is accurate for small distances and widely used in navigation.
Tips & Common Mistakes
Tips
- Ensure latitudes are between -90 and 90, and longitudes between -180 and 180. Use negative values for south and west coordinates.
- For Earth, use a sphere radius of approximately 6371 km for a good average. For more precise results, consider the Earth's ellipsoidal shape.
- The haversine formula assumes a perfect sphere, so results may differ slightly from actual distances on Earth's irregular surface.
- Double-check that both points use the same coordinate system (e.g., decimal degrees) before entering them.
Common Mistakes to Avoid
- Entering latitude and longitude in the wrong order. Latitude is the first field, longitude is the second.
- Using degrees instead of radians. This calculator expects degrees, so do not convert to radians manually.
- Forgetting to use negative signs for southern latitudes or western longitudes, which can lead to incorrect distances.
Last updated: August 13, 2026