How Flight Distance Is Measured for EU261 and UK261
EU261 and UK261 measure distance as a great circle — the shortest path over the Earth's surface — between the airport you leave from and your final destination. Article 7(4): "The distances given in paragraphs 1 and 2 shall be measured by the great circle route method." The distance then picks the band: up to 1,500 km, up to 3,500 km, or beyond.
The formula
With each airport's latitude and longitude in radians, the haversine formula gives the great-circle distance d on a sphere of radius R:
d = 2R · asin( √( sin²(Δlat/2) + cos(lat₁) · cos(lat₂) · sin²(Δlon/2) ) )
This site uses R = 6,371 km, the mean Earth radius, and the coordinates published by OurAirports (or the airport's Wikipedia entry where OurAirports could not be read). The same code runs in the checker and builds every route page.
Worked examples
| Route | From | To | Distance | EU261 band | UK261 band |
|---|---|---|---|---|---|
| LHR–JFK | 51.470748, -0.459909 | 40.639722, -73.778889 | 5,540 km | €600 | £520 |
| LGW–BCN | 51.148744, -0.185739 | 41.2971, 2.07846 | 1,109 km | €250 | £220 |
| HEL–TFS | 60.318363, 24.963341 | 28.0445, -16.5725 | 4,742 km | €400 | not UK |
London Heathrow to New York JFK comes out at 5,540 km — comfortably in the top band. Gatwick to Barcelona, 1,109 km, is short-haul. Helsinki to Tenerife, 4,742 km, is longer than many transatlantic flights, but both airports are in the EU, so it pays the flat €400 for intra-EU flights over 1,500 km rather than €600.
Connections
The distance runs to the final destination on the booking, because Article 7(1) takes as its basis "the last destination at which the denial of boarding or cancellation will delay the passenger's arrival after the scheduled time". If a late first leg makes you miss a connection and you reach the end of the trip 3+ hours late, measure from the first departure airport to the last arrival airport, not the leg that was late. A short feeder flight can therefore lead to a long-haul payment.
Close to a boundary
A route near 1,500 or 3,500 km can come out on either side depending on the coordinates and Earth radius used. Different calculators can differ by a few kilometres; the airline's figure is the one to challenge if it puts you in a lower band. The distance band pages list every route on this site with its computed distance.
Sources
- Regulation (EC) No 261/2004 (EUR-Lex) — Article 7(1), 7(4)
- UK Regulation (EC) No 261/2004, Article 7 (legislation.gov.uk)
- OurAirports country data files
Questions
Is EU261 distance the distance the plane flew?
No. Article 7(4) says distances are measured by the great circle route method, the shortest path over the Earth's surface between the two airports, not the flown track.
Which airports count on a connecting trip?
The first departure airport and the final destination. Article 7(1) says the basis is the last destination at which the delay will make you arrive late.
Does distance matter under Canada's or US rules?
No. Canada's APPR pays by hours late and airline size, and US rules pay no delay compensation.