BDST to IRST
-2h 30mBDST
BDSTSOURCEIRST
IRSTGreen rows indicate typical business hours (9 AM - 5 PM)
BDST and IRST on the World Map
The map below highlights the BDST (Bangladesh Standard Time) and IRST (Iran Standard Time) timezone regions across the globe.
BDST – Bangladesh Standard Time
UTC+06:00Bangladesh Standard Time (BDST, UTC+06:00) is the time zone for Bangladesh, 6 hours ahead of UTC.
- •Bangladesh uses a single time zone, UTC+06:00, across the entire country.
- •Bangladesh does not observe daylight saving time, so the offset is fixed all year.
- •Dhaka is one of the most densely populated cities globally.
- •BDST is written here to distinguish it from British Summer Time (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.
Everything You Need to Know About BDST and IRST Time
BDST runs on Bangladesh Standard Time (BDST) at UTC+06:00. IRST runs on Iran Standard Time (IRST) at UTC+03:30. That puts BDST 2 hours 30 minutes behind IRST — a difference of -2h 30m at the current offsets.
In practice, when it is 9:00 AM in BDST it is 6:30 AM in IRST. Midnight in BDST is 9:30 PM in IRST. Neither zone observes daylight saving time, so the offset between them stays constant all year.
BDST to IRST time conversion table
| BDST (BDST) | IRST (IRST) | Day |
|---|---|---|
| 12:00 AM | 9:30 PM | previous day |
| 6:00 AM | 3:30 AM | same day |
| 7:00 AM | 4:30 AM | same day |
| 8:00 AM | 5:30 AM | same day |
| 9:00 AM | 6:30 AM | same day |
| 12:00 PM | 9:30 AM | same day |
| 3:00 PM | 12:30 PM | same day |
| 5:00 PM | 2:30 PM | same day |
| 6:00 PM | 3:30 PM | same day |
| 9:00 PM | 6:30 PM | same day |
Why people convert BDST to IRST time
- Scheduling a call from BDST to IRST: a 10:00 AM start in BDST lands at 7:30 AM in IRST, so you can confirm the slot without doing the arithmetic yourself.
- Finding shared working hours: both BDST and IRST are inside the 9-to-5 working day between 11:30 AM and 5:00 PM BDST time (9:00 AM–2:30 PM IRST). That is roughly 5 hours 30 minutes of usable overlap.
- Keeping family and friends in sync: knowing that 8:00 PM in BDST is 5:30 PM in IRST makes it easy to avoid calling at 3 AM.
- Always state the zone abbreviation, not just the hour. "3:00 PM BDST" is unambiguous; "3 PM" across a -2h 30m gap is not.
- Block 11:30 AM–5:00 PM BDST as the recurring meeting window if you work primarily from BDST and need IRST colleagues present.
About BDST (Bangladesh Standard Time)
Bangladesh Standard Time (BDST) is the single time zone used across Bangladesh, fixed at UTC+06:00 all year. Bangladesh has not observed daylight saving time since a short-lived experiment in 2009, so the gap between Bangladesh and every other zone is constant. Dhaka, the capital, is one of the most densely populated cities in the world. Because the country sits close to the middle of the UTC+06:00 band, solar noon is near 12:00 for most of the year. BDST is listed separately from British Summer Time, which shares the BST abbreviation but is UTC+01:00.
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 BDST and IRST
Both BDST and IRST sit inside the 9 AM – 5 PM working day between 11:30 AM–5:00 PM BDST, which is 9:00 AM–2:30 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
BDST and IRST share 5 hours of working-hours overlap (11:30 AM–5:00 PM BDST), so scheduling a live meeting is straightforward.
BDST is 2 hours 30 minutes behind IRST (BDST UTC+06:00 → IRST UTC+03:30). The shared working window is 11:30 AM–5:00 PM BDST. Remember to re-check around daylight-saving transitions.
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 BDST and IRST?
BDST (BDST, UTC+06:00) is 2 hours 30 minutes behind IRST (IRST, UTC+03:30). The gap is currently -2h 30m.
How do I convert BDST time to IRST time?
Add -2h 30m to BDST local time. For example, 9:00 AM in BDST is 6:30 AM in IRST.
What time is it in IRST right now?
IRST 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 BDST.
What is the best time to call IRST from BDST?
Call between 11:30 AM and 5:00 PM BDST — that maps to 9:00 AM–2:30 PM IRST and keeps both parties inside the working day.
Which is behind, BDST or IRST?
BDST is 2 hours 30 minutes behind IRST. When it is 12:00 PM in BDST it is 9:30 AM in IRST.
Does daylight saving time affect the BDST–IRST difference?
Neither zone observes daylight saving time, so the -2h 30m offset between BDST and IRST is fixed all year.
Which other cities share BDST's time zone?
BDST also covers Dhaka, Chittagong, Khulna, Rajshahi, Sylhet.
Which countries use BDST, BDST's zone?
BDST is used in Bangladesh.
Is there a day difference between BDST and IRST?
Not normally. The -2h 30m gap only pushes the date over the previous day.
What is the time difference between BDST and IRST?
IRST is -2h 30m from BDST.
What timezone is BDST in?
BDST operates on its local timezone.
What timezone is IRST in?
IRST operates on its local timezone.
Which countries use BDST (Bangladesh Standard Time)?
BDST is used in Bangladesh.
Does BDST observe daylight saving time?
No, BDST does not observe daylight saving time and remains at UTC+06:00 year-round.
What are some interesting facts about BDST?
Bangladesh uses a single time zone, UTC+06:00, across the entire country. Bangladesh does not observe daylight saving time, so the offset is fixed all year.
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 BDST, what time is it in IRST?
When it is 12:00 AM (midnight) in BDST (BDST), it is -2h 30m later in IRST (IRST).
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See every conversion from BDST →·See every conversion from IRST →