Great-circle distance.
Great-circle distance is the distance between two points on the surface of a sphere, measured along the great-circle arc through both, which is the minimum path over that surface. In aviation, the great-circle distance between airports is the baseline for flight planning and quoting trip length, although flown routes are longer because of airways and weather.
| Term | Great-circle distance |
|---|---|
| Used in | Private aviation, charter brokerage and operations |
| Related terms | Nautical mile, Range, Tech stop |
| Sources | 1 listed below |
What does Great-circle distance mean in practice?
When a broker states a trip distance in nautical miles, they usually mean great-circle distance, computed from the latitude and longitude of the two airports.
Formulas applied to Earth's real shape are accurate to within about 0.5 percent, which is close enough for quoting. The aircraft will fly further. Air traffic control routes follow published airways, avoid military and restricted airspace, and route around weather, so the flown distance and time exceed the great-circle figure. On long sectors, the crew may also choose a route that trades distance for favourable winds. For a traveller, the useful points are two. Compare an aircraft's stated range with the great-circle distance and leave a margin, since reserves, headwinds and payload all reduce achievable range. And do not be surprised if the flight plan shows a longer distance than an online calculator: that is normal.
Questions
What does Great-circle distance mean?
Great-circle distance is the distance between two points on the surface of a sphere, measured along the great-circle arc through both, which is the minimum path over that surface. In aviation, the great-circle distance between airports is the baseline for flight planning and quoting trip length, although flown routes are longer because of airways and weather.
Sources
- Wikipedia: Great-circle distance (accessed 2026-09-20)
Last reviewed 20 September 2026 by Empty Leg Exclusive Editorial Team.