How it works
The estimator computes the great-circle distance between two cities and divides it by a typical cruise speed (720–870 km/h depending on distance), then adds a 45-minute ground buffer for taxi, take-off and landing.
The result is rounded to a range of roughly ±10% (at least ±25 minutes) so the estimate reflects day-to-day variation in winds, routing and air traffic instead of a false sense of precision.
Worked example
Shanghai to London is about 9,200 km as the crow flies. At cruise speed plus the ground buffer, the estimate is about 11 hours 20 minutes, with a range of roughly ±1 hour.
If you depart Shanghai at 09:00 local time, the estimated arrival in London is around 13:20 local time—somewhere between 11:50 and 14:50 depending on the actual flight time. Eastbound flights are often faster and westbound slower because of the jet stream.
When to use it
Use it to judge whether you can still catch the last train or bus after landing, whether to book a hotel near the airport for the first night, and roughly when to tell someone you will arrive.
It is also handy for comparing the time cost of a direct flight with a connection before you open the booking site.
Common mistakes
Common mistakes include treating the estimate as an exact schedule, forgetting that the same route takes different times eastbound and westbound, and planning a tight connection using only the estimated flight time.
Minimum connection times depend on the airport, the airlines and visa requirements, so always check the booking confirmation rather than the estimate.
Basis and limits
Distance uses the great-circle formula between city coordinates; real flight paths are slightly longer. Cruise speed and the ground buffer are typical assumptions, not any specific airline's schedule.
Scheduled times change with the airline's timetable and vary daily with wind and weather. Use this tool for rough planning only, and confirm exact times with the airline or booking site.