IRST to BDST
+2h 30mIRST
IRSTSOURCEBDST
BDSTGreen rows indicate typical business hours (9 AM - 5 PM)
IRST and BDST on the World Map
The map below highlights the IRST (Iran Standard Time) and BDST (Bangladesh Standard Time) timezone regions across the globe.
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.
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).
Everything You Need to Know About IRST and BDST Time
IRST runs on Iran Standard Time (IRST) at UTC+03:30. BDST runs on Bangladesh Standard Time (BDST) at UTC+06:00. That puts IRST 2 hours 30 minutes ahead of BDST — a difference of +2h 30m at the current offsets.
In practice, when it is 9:00 AM in IRST it is 11:30 AM in BDST. Midnight in IRST is 2:30 AM in BDST. Neither zone observes daylight saving time, so the offset between them stays constant all year.
IRST to BDST time conversion table
| IRST (IRST) | BDST (BDST) | 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 IRST to BDST time
- Scheduling a call from IRST to BDST: a 10:00 AM start in IRST lands at 12:30 PM in BDST, so you can confirm the slot without doing the arithmetic yourself.
- Finding shared working hours: both IRST and BDST are inside the 9-to-5 working day between 9:00 AM and 2:30 PM IRST time (11:30 AM–5:00 PM BDST). That is roughly 5 hours 30 minutes of usable overlap.
- Watching a live event or market open: IRST viewers need 11:30 AM in BDST to catch a 9:00 AM start there, and 9:30 PM if the event is anchored to IRST.
- Always state the zone abbreviation, not just the hour. "3:00 PM IRST" is unambiguous; "3 PM" across a +2h 30m gap is not.
- Block 9:00 AM–2:30 PM IRST as the recurring meeting window if you work primarily from IRST and need BDST colleagues present.
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.
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.
Best time to call between IRST and BDST
Both IRST and BDST sit inside the 9 AM – 5 PM working day between 9:00 AM–2:30 PM IRST, which is 11:30 AM–5:00 PM BDST. That gives roughly 5 hours and 30 minutes of shared time — the safest window for a live call or meeting.
Business hours overlap
IRST and BDST share 5 hours of working-hours overlap (9:00 AM–2:30 PM IRST), so scheduling a live meeting is straightforward.
IRST is 2 hours 30 minutes ahead of BDST (IRST UTC+03:30 → BDST UTC+06:00). The shared working window is 9:00 AM–2:30 PM IRST. 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 IRST and BDST?
IRST (IRST, UTC+03:30) is 2 hours 30 minutes ahead of BDST (BDST, UTC+06:00). The gap is currently +2h 30m.
How do I convert IRST time to BDST time?
Add +2h 30m to IRST local time. For example, 9:00 AM in IRST is 11:30 AM in BDST.
What time is it in BDST right now?
BDST uses BDST at UTC+06:00. Use the live converter at the top of this page — it updates in real time and already accounts for the +2h 30m offset from IRST.
What is the best time to call BDST from IRST?
Call between 9:00 AM and 2:30 PM IRST — that maps to 11:30 AM–5:00 PM BDST and keeps both parties inside the working day.
Which is ahead, IRST or BDST?
IRST is 2 hours 30 minutes ahead of BDST. When it is 12:00 PM in IRST it is 2:30 PM in BDST.
Does daylight saving time affect the IRST–BDST difference?
Neither zone observes daylight saving time, so the +2h 30m offset between IRST and BDST is fixed all year.
Which other cities share IRST's time zone?
IRST also covers Tehran, Isfahan, Mashhad, Tabriz, Shiraz, Karaj.
Which countries use IRST, IRST's zone?
IRST is used in Iran.
Is there a day difference between IRST and BDST?
Not normally. The +2h 30m gap only pushes the date over for late-evening times.
What is the time difference between IRST and BDST?
BDST is +2h 30m from IRST.
What timezone is IRST in?
IRST operates on its local timezone.
What timezone is BDST in?
BDST operates on its local timezone.
Which countries use IRST (Iran Standard Time)?
IRST is used in Iran.
Does IRST observe daylight saving time?
Yes, IRST switches to IRDT during summer months.
What are some interesting facts about IRST?
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).
Which cities are in the BDST timezone?
Major cities in the BDST timezone include Dhaka, Chittagong, Khulna, Rajshahi, Sylhet.
What is the UTC offset for BDST?
Bangladesh Standard Time (BDST) is at UTC+06:00.
What should I know about the BDST timezone?
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.
When is it midnight in IRST, what time is it in BDST?
When it is 12:00 AM (midnight) in IRST (IRST), it is +2h 30m later in BDST (BDST).
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