BST to Tehran
+2h 30mBST
BSTSOURCETehran
IRSTGreen rows indicate typical business hours (9 AM - 5 PM)
BST and IRST on the World Map
The map below highlights the BST (British Summer Time) and IRST (Iran Standard Time) timezone regions across the globe.
BST – British Summer Time
UTC+01:00British Summer Time (BST, UTC+01:00) is the daylight saving period in the United Kingdom, running from late March to late October.
- •BST runs from the last Sunday in March to the last Sunday in October.
- •BST is exactly one hour ahead of GMT, the UK's standard time.
- •During BST, London is 4 hours ahead of New York while the US is on Eastern Daylight Time.
- •The Isle of Man and the Channel Islands also observe BST.
IRST – Iran Standard Time
UTC+03:30Iran Standard Time (IRST) is the time zone for Iran, 3 hours and 30 minutes ahead of UTC.
- •IRST is one of only a few time zones with a 30-minute offset.
- •Iran observes daylight saving time, switching to IRDT (UTC+04:30).
- •Tehran has a metropolitan population of over 16 million.
About Tehran
WikipediaTehran operates on Iran Standard Time (IRST), UTC+3:30. Iran's unique half-hour offset makes Tehran time distinctive for regional business coordination.
Iran Standard Time (IRST) is one of few timezones with a 30-minute offset (UTC+3:30).
BST to Tehran Time Difference – Complete Guide
BST runs on British Summer Time (BST) at UTC+01:00. Tehran runs on Iran Standard Time (IRST) at UTC+03:30. That puts BST 2 hours 30 minutes ahead of Tehran — a difference of +2h 30m at the current offsets.
In practice, when it is 9:00 AM in BST it is 11:30 AM in Tehran. Midnight in BST is 2:30 AM in Tehran. Neither zone observes daylight saving time, so the offset between them stays constant all year.
BST to Tehran time conversion table
| BST (BST) | Tehran (IRST) | Day |
|---|---|---|
| 12:00 AM | 2:30 AM | same day |
| 6:00 AM | 8:30 AM | same day |
| 7:00 AM | 9:30 AM | same day |
| 8:00 AM | 10:30 AM | same day |
| 9:00 AM | 11:30 AM | same day |
| 12:00 PM | 2:30 PM | same day |
| 3:00 PM | 5:30 PM | same day |
| 5:00 PM | 7:30 PM | same day |
| 6:00 PM | 8:30 PM | same day |
| 9:00 PM | 11:30 PM | same day |
Why people convert BST to Tehran time
- Scheduling a call from BST to Tehran: a 10:00 AM start in BST lands at 12:30 PM in Tehran, so you can confirm the slot without doing the arithmetic yourself.
- Finding shared working hours: both BST and Tehran are inside the 9-to-5 working day between 9:00 AM and 2:30 PM BST time (11:30 AM–5:00 PM IRST). That is roughly 5 hours 30 minutes of usable overlap.
- Watching a live event or market open: BST viewers need 11:30 AM in Tehran to catch a 9:00 AM start there, and 9:30 PM if the event is anchored to BST.
- Always state the zone abbreviation, not just the hour. "3:00 PM BST" is unambiguous; "3 PM" across a +2h 30m gap is not.
- Block 9:00 AM–2:30 PM BST as the recurring meeting window if you work primarily from BST and need Tehran colleagues present.
About BST (British Summer Time)
British Summer Time (BST) is the daylight saving period in the United Kingdom, when clocks move one hour forward from Greenwich Mean Time (GMT, UTC+00:00) to UTC+01:00. It runs from the last Sunday in March to the last Sunday in October. England, Scotland, Wales and Northern Ireland all follow it, along with the Isle of Man and the Channel Islands of Jersey and Guernsey. During BST, London is one hour ahead of UTC, four hours ahead of New York on Eastern Daylight Time, and five hours ahead of New York once the United States returns to Eastern Standard Time in November. BST is also used to abbreviate Bangladesh Standard Time (UTC+06:00), which is listed separately on this site.
About IRST (Iran Standard Time)
Iran Standard Time (IRST) is one of the few time zones with a 30-minute offset. Iran observes daylight saving time (IRDT, UTC+04:30) from late March to late September. Tehran, the capital, is one of the largest cities in the Middle East.
Best time to call between BST and Tehran
Both BST and Tehran sit inside the 9 AM – 5 PM working day between 9:00 AM–2:30 PM BST, which is 11:30 AM–5:00 PM IRST. That gives roughly 5 hours and 30 minutes of shared time — the safest window for a live call or meeting.
Business hours overlap
BST and Tehran share 5 hours of working-hours overlap (9:00 AM–2:30 PM BST), so scheduling a live meeting is straightforward.
BST is 2 hours 30 minutes ahead of Tehran (BST UTC+01:00 → IRST UTC+03:30). The shared working window is 9:00 AM–2:30 PM BST. Remember to re-check around daylight-saving transitions.
🕐 Daylight Saving Time Info
BST
☀ Currently in DST
Standard: UTC+00:00 · DST: UTC+01:00
Clocks fall back on Sun, Oct 25, 2026
Tehran
Does not observe DST
Learn More About Time
Dive deeper into the fascinating world of timekeeping, time zones, and how they shape our global society:
Frequently Asked Questions
What is the time difference between BST and Tehran?
BST (BST, UTC+01:00) is 2 hours 30 minutes ahead of Tehran (IRST, UTC+03:30). The gap is currently +2h 30m.
How do I convert BST time to Tehran time?
Add +2h 30m to BST local time. For example, 9:00 AM in BST is 11:30 AM in Tehran.
What time is it in Tehran right now?
Tehran uses IRST at UTC+03:30. Use the live converter at the top of this page — it updates in real time and already accounts for the +2h 30m offset from BST.
What is the best time to call Tehran from BST?
Call between 9:00 AM and 2:30 PM BST — that maps to 11:30 AM–5:00 PM IRST and keeps both parties inside the working day.
Which is ahead, BST or Tehran?
BST is 2 hours 30 minutes ahead of Tehran. When it is 12:00 PM in BST it is 2:30 PM in Tehran.
Do BST and Tehran use different time zones?
BST uses BST at UTC+01:00, while Tehran (Iran) uses IRST at UTC+03:30. The IANA identifiers are Europe/London and Asia/Tehran.
Does daylight saving time affect the BST–Tehran difference?
Neither zone observes daylight saving time, so the +2h 30m offset between BST and Tehran is fixed all year.
Which other cities share BST's time zone?
BST also covers London, Birmingham, Manchester, Glasgow, Edinburgh, Cardiff, Belfast, Liverpool and 2 more.
Which countries use BST, BST's zone?
BST is used in United Kingdom.
Is there a day difference between BST and Tehran?
Not normally. The +2h 30m gap only pushes the date over for late-evening times.
What is the time difference between BST and Tehran?
Tehran is +2h 30m from BST.
What timezone is BST in?
BST operates on its local timezone.
What timezone is Tehran in?
Tehran operates on Iran Standard Time (IRST), UTC+3:30. Iran's unique half-hour offset makes Tehran time distinctive for regional business coordination.
What are the business hours in Tehran?
Standard business hours in Tehran are 8:00 AM - 4:00 PM IRST.
Which countries use BST (British Summer Time)?
BST is used in United Kingdom.
Does BST observe daylight saving time?
Yes, BST switches to BST during summer months.
What are some interesting facts about BST?
BST runs from the last Sunday in March to the last Sunday in October. BST is exactly one hour ahead of GMT, the UK's standard time.
Which cities are in the IRST timezone?
Major cities in the IRST timezone include Tehran, Isfahan, Mashhad, Tabriz, Shiraz, Karaj.
What is the UTC offset for IRST?
Iran Standard Time (IRST) is at UTC+03:30. During daylight saving time, it shifts to IRDT.
What should I know about the IRST timezone?
IRST is one of only a few time zones with a 30-minute offset. Iran observes daylight saving time, switching to IRDT (UTC+04:30).
When is it midnight in BST, what time is it in Tehran?
When it is 12:00 AM (midnight) in BST (BST), it is +2h 30m later in Tehran (IRST).
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