Using the great-circle calculator
Compare two airports or geographic points to find their direct distance and departure and arrival true tracks. Choose Point A and Point B with ICAO airport codes, coordinates, or map clicks. The route appears on the map, with distance in nautical miles and kilometres. Swap A / B to check the reverse direction; clear the route to start again.
Distance and true track
A great circle follows the shortest path across a spherical Earth. On a flat map, that path often looks curved, especially on long flights at higher latitudes. True track is measured clockwise from geographic north, rather than magnetic north. The initial and final tracks can differ because the direction changes along the curve. Opposite points have no unique shortest route; coincident points have no defined track.
Airport and coordinate input
Use a four-letter ICAO code such as YBBN, or enter latitude followed by longitude. Airport suggestions also help you search by name. Decimal degrees, degrees and decimal minutes, and degrees/minutes/seconds are supported. Check hemisphere letters and signs carefully: south and west are negative in signed decimal input. Coordinates let you compare remote locations as well as airports.
Basic and Advanced mode
Basic opens by default and shows distance and true tracks. Advanced adds cruise speed, a cruise flight-level dropdown and 24-hour departure time. Departure defaults to local time when Point A has a reliable timezone; switch Local / UTC to view or enter the same instant. Otherwise UTC is used. Destination-local arrival is shown first, with UTC (Zulu) always visible. Compare forecast winds over a level range to find the fastest wind level, with time saved against your selected level. Arrival and day, civil twilight or night use the selected level. The still-air reference remains visible. Switching modes preserves settings.
What the estimate leaves out
Forecast estimates sample wind and temperature along the route through flight time, using NOAA GFS via Open-Meteo. Mach uses forecast temperature when available. Missing data or times beyond forecast coverage fall back to still air. Fastest wind level compares weather, not aircraft performance or permitted altitudes. Airway routing, climb, descent and taxi remain excluded. Use this planning reference alongside current operational information.
Frequently asked questions
What is great-circle distance?
It is the shortest surface distance between two points on a sphere. This calculator uses a mean Earth radius of 6,371.0088 km and reports nautical miles and kilometres. It is a direct-route reference, not the distance of an airway or cleared flight plan.
Can I enter coordinates instead of airports?
Yes. Enter latitude first, then longitude, using decimal degrees or degrees and minutes/seconds. Examples include -27.5, 153.125 and 27°30′00″S 153°07′30″E. You can mix an ICAO airport at one end with coordinates at the other. IATA codes are not supported.
How are TAS and Mach flight-time estimates calculated?
Still-air time is distance divided by TAS. Mach uses ISA temperature for the still-air reference and sampled forecast temperature for wind estimates. Advanced compares flight levels using a constant cruise setting along the direct route.
Does the result include wind?
Advanced can sample NOAA GFS wind and temperature via Open-Meteo as the flight progresses. It includes headwind, tailwind and crosswind correction, compares candidate levels and shows the fastest wind level. Missing forecasts fall back to clearly labelled still-air estimates. Aircraft performance, climb, descent, taxi and routing restrictions are excluded.