Find arrival local time after a flight.
Arrival local time is departure time plus flight duration plus the offset between the two zones — the addition people get wrong is the offset, because it makes the clock jump without any time passing. Eastbound flights land at a later clock time than the elapsed hours suggest and can cross into the next calendar day; westbound flights can land at an earlier clock time than they departed. The body clock figure is departure plus duration with no offset applied, which is the number that actually predicts how tired you will be on arrival.
Arrival local time
Arrival = departure time + flight hours + destination offset, wrapped at 24 h; body clock = departure + flight hours only
Subtract the origin's UTC offset from the destination's. London (UTC+1 in summer) to Dubai (UTC+4) is +3. Check both on the travel date, because daylight saving transitions can change the gap by an hour.
On long westbound routes the offset is negative and larger than the flight duration, so the arrival clock time precedes the departure clock time. No time is gained — the elapsed hours figure shows what actually passed.
The body clock time. Landing at 08:00 local after a flight your body reads as 03:00 is why morning arrivals eastbound are hard, and it is the mismatch that determines how you should schedule the first day.