Real flight duration
Enter departure and arrival local time and UTC offset (and the day difference): calculate the actual flight duration.
What it's for
Ticket times are always local: to know how long a flight really lasts you must account for the time zone change. This tool does it for you.
How to fill it in
Enter each city's UTC offset (e.g. Italy +2 in summer, New York -4). If the flight arrives the next day, set «+ days» to 1.
Why ticket times mislead
A ticket shows two local times, and subtracting one from the other does not give the flight duration: it gives the duration plus the time difference. Rome to New York leaves at 10:30 and lands at 14:00, «three and a half hours» that are really nine.
The direction changes everything: heading west you «gain» time and land at almost the hour you left, heading east you lose it and land the next day. It is the same flight, the same length, that on paper looks half or twice as long.
Block time, not time in the air
The duration an airline publishes is «block time»: from the moment the aircraft pushes back from the gate to the moment it stops at the arrival gate. It includes taxiing, which at a big airport can be twenty minutes, not only the time actually spent flying.
Airlines also build a safety margin into the schedule, wider the more congested the airport: it is why a flight can arrive «early» with suspicious regularity. It protects punctuality statistics and connections.
Out and back do not take the same time
On long routes the return leg can be a good hour shorter, and the cause is the jet stream: a very fast river of air at altitude flowing from west to east. Flying inside it pushes you along, flying against it holds you back.
That is why New York to London is shorter than London to New York, usually six and a half hours against eight. The gap changes with the season, because the stream is stronger in winter, and it is also why some routes need a technical stop in one direction only.
Nearby tools
The exact time at your destination comes from World clock and the straight-line distance from Distance between cities. To get back on schedule after the flight there is Jet lag calculator.