How to Work Out a Flight's Arrival Time (with Time Zones)

By Lokesh RathoreUpdated 26 Aug 2026 · 6 min read

"Departure plus flight time" sounds like all you need to know what time you will land. Then time zones get involved, and a fifteen-hour flight can land before lunch on the same day you left. Here is the simple way to work out a flight's real arrival time in the destination's local clock, with three worked examples, including the kind that turns up in exam papers.

The simple method, in three steps

Whatever the route, the same three steps work:

1. Write down your departure time in the clock of the city you are leaving.
2. Add the flight time. This is when you would land if the destination kept the same clock as home.
3. Shift by the time difference between the two cities: add the hours if your destination is ahead, take them off if it is behind. That gives the real local arrival time.

And keep an eye on the date, because the answer can roll over to the next day, or even land you "earlier" than you set off.

One warning before the examples. Doing this by hand fails in a way that is easy to miss: the offset between two places is not a constant. Much of Europe and North America shifts by an hour for daylight saving, India never does, so the India–UK gap is 4h 30m in summer and 5h 30m in winter — and it changes on different dates in each country. India's own half-hour offset, Nepal's 45-minute one and Australia's mixed zones make it worse.

This is why the calculator does not store offsets at all. It stores each airport's IANA time-zone name — Asia/Kolkata, Europe/London — and resolves the real offset for the actual date you are flying. That is the same database your phone and your laptop use, maintained as governments change their rules. If you are working it out by hand, look up the offset for your travel date, not today's.

On the time-zone database and why offsets move: IANA Time Zone Database.

Example 1: a short hop, Delhi to Dubai

Say you leave Delhi at 09:00 on a flight of about 3 hours 15 minutes. Dubai runs 1 hour 30 minutes behind India.

• Step 1: depart 09:00 (Delhi time).
• Step 2: 09:00 plus 3h 15m is 12:15, still on the Delhi clock.
• Step 3: Dubai is 1h 30m behind, so take off 1h 30m. 12:15 becomes 10:45.

You land at about 10:45 the same morning, Dubai time. The clock barely moves, because the two cities are close in time.

Example 2: the classic exam question, Sydney to Beijing

This is the kind of question that shows up in maths and aptitude papers: a flight leaves Sydney at 19:30 and takes 11 hours 45 minutes; Beijing is 2 hours behind Sydney; what time does it arrive?

• Step 1: depart 19:30 (Sydney time).
• Step 2: 19:30 plus 11h 45m is 07:15 the next morning, on the Sydney clock.
• Step 3: Beijing is 2 hours behind, so take off 2 hours. 07:15 becomes 05:15.

The flight lands at 05:15 the next day, Beijing time. The overnight flight crosses into tomorrow, so the date moves on by one.

Example 3: the time-traveller, Delhi to New York

Now a long westbound haul. You leave Delhi at 02:00 on a flight of about 15 hours 12 minutes. New York runs 9 hours 30 minutes behind India.

• Step 1: depart 02:00 (Delhi time).
• Step 2: 02:00 plus 15h 12m is 17:12 on the Delhi clock.
• Step 3: New York is 9h 30m behind, so take off 9h 30m. 17:12 becomes 07:42.

You leave at 2 in the morning, spend over fifteen hours in the air, and still land at 07:42 the same morning in New York, only about five and a half hours later on the clock than you set off. Flying west you claw back so many hours that a fifteen-hour flight barely moves the local time. On a shorter westbound hop the gain can be bigger than the flight itself, and then you really do land at an earlier clock time than you took off. One caveat on all three examples: the exact time gap shifts by an hour when a country is on daylight saving, so check the current offset for your travel dates.

Why the date jumps, or goes backwards

The date follows the same logic. Flying east you lose hours and often land the next day, which is why a flight to Australia or Japan so often arrives "tomorrow". Flying west you gain hours, so you can land on the same calendar day you departed, sometimes at an earlier clock time than your take-off. Nothing is broken; you are simply crossing the lines where the clocks change.

The easy way: let the calculator do it

Working this out by hand is fine for one trip, but the time difference is the fiddly part, especially with daylight saving in the mix. The flight time calculator on this site does all three steps for you: enter your two airports and a departure time, and it gives the arrival in the destination's local clock, tells you whether you land the next day, and shows the exact time-zone gap. If you also want to understand the flight-time part, see how flight time is calculated, and our jet lag guide for what that time difference does to your body.

So next time you book, you do not have to guess what the clock will say when you land. Add the flight time, shift for the time zone, and watch the date. Or just let the tool do the arithmetic and tell you exactly when to ask someone to pick you up.