London to IRST
Converting a fixed time. Europe/London → Asia/Tehran
Clocks go back 1 hour on Sunday, 25th October 2026, at 1:59 am local time (1:00 am after the change).
Clocks here do not change — this zone stays on the same offset all year.
Convert a specific time minutes work, not just whole hours
Hour by hour
| London | IRST | 24h | Good to call? |
|---|---|---|---|
| 12am now | 2am | 00:00 → 02:30 | asleep in IRST |
| 1am | 3am | 01:00 → 03:30 | asleep in IRST |
| 2am | 4am | 02:00 → 04:30 | asleep in IRST |
| 3am | 5am | 03:00 → 05:30 | asleep in IRST |
| 4am | 6am | 04:00 → 06:30 | asleep in IRST |
| 5am | 7am | 05:00 → 07:30 | asleep in London |
| 6am | 8am | 06:00 → 08:30 | asleep in London |
| 7am | 9am | 07:00 → 09:30 | awake, not at work |
| 8am | 10am | 08:00 → 10:30 | awake, not at work |
| 9am | 11am | 09:00 → 11:30 | both at work |
| 10am | 12pm | 10:00 → 12:30 | both at work |
| 11am | 1pm | 11:00 → 13:30 | both at work |
| 12pm | 2pm | 12:00 → 14:30 | both at work |
| 1pm | 3pm | 13:00 → 15:30 | both at work |
| 2pm | 4pm | 14:00 → 16:30 | both at work |
| 3pm | 5pm | 15:00 → 17:30 | awake, not at work |
| 4pm | 6pm | 16:00 → 18:30 | awake, not at work |
| 5pm | 7pm | 17:00 → 19:30 | awake, not at work |
| 6pm | 8pm | 18:00 → 20:30 | awake, not at work |
| 7pm | 9pm | 19:00 → 21:30 | awake, not at work |
| 8pm | 10pm | 20:00 → 22:30 | asleep in IRST |
| 9pm | 11pm | 21:00 → 23:30 | asleep in IRST |
| 10pm | 12am Sat | 22:00 → 00:30 | asleep in IRST |
| 11pm | 1am Sat | 23:00 → 01:30 | asleep in IRST |
Call times
Both places are at work between 9am and 15:00 in London — 11am to 4pm at the other end.
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Questions people ask
What time is it in IRST when it is 5:00 pm in London?
7:30 pm in IRST the same day.
How many hours ahead is IRST of London?
IRST is 2 hours 30 minutes ahead London. That gap is not fixed: it changes when either place starts or ends daylight saving. The table on this page is recalculated for today, so it is already correct for the current season.
What is the best time to call between London and IRST?
Both places are at work between 9am and 15:00 in London — 11am to 4pm at the other end.
When does the difference between London and IRST change?
London: Clocks go back 1 hour on Sunday, 25th October 2026, at 1:59 am local time (1:00 am after the change). IRST does not change its clocks, so the gap shifts by an hour on that date.