Key facts
- Method: great-circle (geodesic) distances between airport reference points on the WGS84 ellipsoid with GeographicLib; 4,517 airports with IATA codes from OurAirports (public domain); flight time = distance at 800 km/h plus 30 minutes per leg.
- Runs in your browser: what you click, draw or open is not uploaded.
- Data and libraries: OpenFreeMap, MapLibre GL JS, GeographicLib (geographiclib-geodesic), OurAirports, timezone-boundary-builder (via geo-tz), IANA time zone database (tz database), in your browser.
- Free to use, with no sign-up and nothing to install.
Airlines, frequent-flyer programmes, travel-expense rules and the EU rules on flight compensation all count a flight's length the same way: as the great-circle distance between the two airports, the shortest line over the curved Earth. That line looks bent on a flat map, which is why a flight from New York to London heads north-east past Newfoundland and a flight from Tokyo to London crosses Siberia far north of the Arctic Circle. This calculator takes the airports by their three-letter IATA codes (JFK, LHR, CDG) or four-letter ICAO codes (KJFK, EGLL), by a search for the airport or city name, or as the nearest airport to a point you click on the map. Type a whole itinerary in one line, such as CPH-DXB-SYD, to get every leg, the total, and how much longer the stopovers make the trip than flying direct. For each flight it gives the distance in kilometres, statute miles and nautical miles, the heading at take-off and on arrival, how far north or south the great circle takes you, the longer rhumb line of constant compass heading for comparison, the time difference between the first and last airport and a rough flight time. The list of 4,517 airports with scheduled or regional traffic comes from OurAirports and is searched in your browser.
How to use it
- Type the airport codes in the order you fly, for example JFK LHR or CPH-DXB-SYD, and press "Show route".
- Or search an airport by name, city or code and pick it from the list, or click on the map to add the nearest airport.
- Read the great-circle distance in km, miles and nautical miles, the flight time estimate and the headings, and see the route on the map.
- Download the legs as CSV, the route as KML or GeoJSON, or copy the share link.
Worked example: New York to London, and Copenhagen to Sydney via Dubai
JFK to LHR is 5,555 km, 3,451 miles or 2,999 nautical miles along the great circle. The aircraft leaves New York on a heading of 51° (north-east), reaches its most northerly point at 53.7° N over the Atlantic west of Ireland, and arrives over London heading 108°. A rhumb line, flying the same compass heading all the way, would be 5,774 km, 3.9 % longer. The rough flight time is 7 h 25 min; with the usual jet stream the real flight east is shorter and the flight west longer. Typed as CPH-DXB-SYD, the route is 4,821 km to Dubai plus 12,039 km to Sydney, 16,860 km in all, against 16,035 km direct, so the stop in Dubai adds 5.1 %.
What people use it for
- Checking whether a delayed or cancelled flight is over 1,500 or 3,500 km for EU 261 compensation.
- Counting flown miles for a frequent-flyer programme, a travel-expense claim or a carbon-footprint estimate.
- Comparing itineraries with different stopovers, and seeing why long-haul routes curve towards the poles.
How accurate is it?
Great-circle distance on the ellipsoid
Each leg is the geodesic between the two airports on the WGS84 ellipsoid, computed with Charles Karney's GeographicLib, the same method used by aviation and geodesy software. It is exact to well under a metre between the points used. A spherical formula such as haversine, used by many flight-distance sites, can be off by up to 0.5 %; between New York and London it gives 5,540 km, 15 km short. Each airport is its reference point from OurAirports, usually near the middle of the runways, so the result can differ by a kilometre or two from a distance measured gate to gate.
The distance flown is longer
Aircraft follow airways, departure and arrival procedures and wind-optimised tracks, and they avoid closed or restricted airspace, so the distance actually flown is usually 2–8 % longer than the great circle, and more on routes that avoid a region. Cruising at 11 km altitude adds another 0.17 %, about 10 km on a transatlantic flight. Airlines, frequent-flyer programmes and the EU compensation rules use the great-circle distance anyway, because it is the same for every flight on the route.
Flight time is a rule of thumb
The flight time is the distance at an average 800 km/h plus 30 minutes for take-off, climb, approach and landing, per leg and rounded to 5 minutes, without time on the ground at stopovers. Winds change real block times by up to an hour on long flights: eastbound over the North Atlantic is often 45–60 minutes faster than westbound. Use the airline's timetable for the actual schedule.
Good to know
Codes for cities and airports
Some three-letter codes stand for a whole city with several airports, such as LON for London, NYC for New York or PAR for Paris. They are not airports, so the calculator asks for the airport itself: LHR, LGW, STN, LTN or LCY for London; JFK, LGA or EWR for New York. Search the city name to see its airports. The same city can be 50 km wider than you think: Stansted is 67 km from Heathrow.
The map line looks curved
On a web map in the Mercator projection the shortest route bends towards the pole, and a straight line on the map is the longer rhumb line. The curve drawn on the map is the true shortest route. Long flights over the Pacific may cross the 180° meridian; the line is drawn continuously across it.
Small airfields are not in the list
The list holds the 4,517 medium and large airports with an IATA code: every airport with scheduled flights and many regional ones. Small airfields, heliports and private strips are left out to keep the list small and the search fast. For any other place, click it on the map to add the nearest airport, or use the distance calculator to measure from any point.
Frequently asked questions
How do I calculate the distance between two airports?
Type the two codes, for example LHR JFK, and press "Show route". The panel shows the great-circle distance, 5,555 km, 3,451 miles or 2,999 nautical miles, with the flight time estimate and the route on the map. You can also search the airports by city name.
Is the distance the same as the miles I fly?
Not quite. The calculator gives the great-circle distance, the shortest path over the Earth. The aircraft usually flies 2–8 % farther because of airways, wind and airspace restrictions. Airlines and frequent-flyer programmes that count distance flown normally use the great-circle distance between the airports, as here.
Is my flight over 1,500 or 3,500 km for EU 261 compensation?
The EU regulation on air passenger rights (EC 261/2004) measures distance by the great-circle method, the same as this calculator. Flights up to 1,500 km and those above 3,500 km fall in different compensation bands; for a connecting flight the distance from the first departure to the final destination usually counts. The calculator only gives the distance; whether compensation is due depends on the rules and the circumstances.
How do I add a stopover?
Type all the codes in the order you fly, such as CPH-DXB-SYD or JFK ORD LAX, separated by dashes or spaces. The table shows each leg, and the panel gives the total, the total flight time and how much longer the route is than flying direct from the first to the last airport. Up to 12 airports fit in one route.
Why does the route on the map curve?
The shortest path on a sphere or ellipsoid is part of a great circle, and on a flat Mercator map a great circle bends towards the nearest pole. From London to Los Angeles the route reaches 62.3° N over southern Greenland. Flying a constant compass heading instead would be 9,756 km, 11 % longer than the 8,781 km great circle.
What is the difference between IATA and ICAO codes?
IATA codes have three letters and are used on tickets and luggage tags, such as AMS for Amsterdam Schiphol. ICAO codes have four letters and are used by pilots and air traffic control, such as EHAM. The calculator accepts both.
Something wrong or missing? E-mail [email protected] and it will be fixed.