Your ticket says you leave Lahore at 3:40 am and land in London at 8:15 am the same day. Is the flight really 4 hours 35 minutes? No, because the two times are in different time zones. This guide shows how to calculate flight duration across time zones step by step, and how our Date & Time Difference tool does it automatically.
The rule
Airline tickets always show local time at each airport. To get the real duration:
- Convert both times to the same time zone (or to UTC).
- Subtract.
Example: Lahore to London (winter)
- Depart Lahore 03:40 PKT (UTC+5) = 22:40 UTC the previous day
- Arrive London 08:15 GMT (UTC+0) = 08:15 UTC
- Duration = 9 hours 35 minutes
In British Summer Time (UTC+1), the same local times would give 8 hours 35 minutes, which is why schedules change in summer.
Example: Karachi to Dubai
- Depart Karachi 21:00 PKT (UTC+5) = 16:00 UTC
- Arrive Dubai 22:15 GST (UTC+4) = 18:15 UTC
- Duration = 2 hours 15 minutes
Example: Islamabad to New York
Long-haul flights often cross dates. If you depart Islamabad at 02:00 PKT on 5 June and arrive in New York at 12:30 EDT (UTC−4) on 5 June:
- Departure: 21:00 UTC on 4 June
- Arrival: 16:30 UTC on 5 June
- Duration = 19 hours 30 minutes, including any layover
Quick reference: UTC offsets
| City | Offset |
|---|---|
| Pakistan | UTC+5 |
| UAE | UTC+4 |
| Saudi Arabia | UTC+3 |
| UK | UTC+0, UTC+1 in summer |
| New York | UTC−5, UTC−4 in summer |
Jet lag
Crossing many time zones disrupts sleep. Adjust gradually before travel, drink water and get daylight at your destination. For a sense of the difference, check both cities in the Time Zone Converter.
Layovers
To find layover time, subtract the arrival time of the first flight from the departure time of the second, both in the connecting airport’s local time.
For other uses of the tool, see time between two dates and times. To convert 12-hour ticket times to 24-hour, use the 12h / 24h / Military Time Converter.
Frequently asked questions
Are flight times on tickets in local time?
Yes, departure and arrival times are local to each airport.
How do I calculate flight duration?
Convert both times to the same time zone, then subtract.
Why do flight durations change in summer?
Daylight saving changes the time difference between some cities.