IRST to WIB
+3h 30mIRST
IRSTSOURCEWIB
WIBGreen rows indicate typical business hours (9 AM - 5 PM)
IRST and WIB on the World Map
The map below highlights the IRST (Iran Standard Time) and WIB (Western Indonesia 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.
WIB – Western Indonesia Time
UTC+07:00Western Indonesia Time (WIB, UTC+07:00) covers Java, Sumatra and West Kalimantan, including Jakarta.
- •Indonesia spans three time zones: WIB (UTC+07:00), WITA (UTC+08:00) and WIT (UTC+09:00).
- •Indonesia has not observed daylight saving time since 1964.
- •Jakarta is the largest city in Southeast Asia by population.
- •WIB shares the UTC+07:00 offset with Indochina Time.
IRST vs WIB: Offsets, DST and Best Call Times
IRST runs on Iran Standard Time (IRST) at UTC+03:30. WIB runs on Western Indonesia Time (WIB) at UTC+07:00. That puts IRST 3 hours 30 minutes ahead of WIB — a difference of +3h 30m at the current offsets.
In practice, when it is 9:00 AM in IRST it is 12:30 PM in WIB. Midnight in IRST is 3:30 AM in WIB. Neither zone observes daylight saving time, so the offset between them stays constant all year.
IRST to WIB time conversion table
| IRST (IRST) | WIB (WIB) | Day |
|---|---|---|
| 12:00 AM | 3:30 AM | same day |
| 6:00 AM | 9:30 AM | same day |
| 7:00 AM | 10:30 AM | same day |
| 8:00 AM | 11:30 AM | same day |
| 9:00 AM | 12:30 PM | same day |
| 12:00 PM | 3:30 PM | same day |
| 3:00 PM | 6:30 PM | same day |
| 5:00 PM | 8:30 PM | same day |
| 6:00 PM | 9:30 PM | same day |
| 9:00 PM | 12:30 AM | next day |
Why people convert IRST to WIB time
- Scheduling a call from IRST to WIB: a 10:00 AM start in IRST lands at 1:30 PM in WIB, so you can confirm the slot without doing the arithmetic yourself.
- Finding shared working hours: both IRST and WIB are inside the 9-to-5 working day between 9:00 AM and 1:30 PM IRST time (12:30 PM–5:00 PM WIB). That is roughly 4 hours 30 minutes of usable overlap.
- Coordinating a IRST-based team with WIB contacts: quoting times in the other side's local clock — not your own — removes the single biggest source of missed meetings.
- Always state the zone abbreviation, not just the hour. "3:00 PM IRST" is unambiguous; "3 PM" across a +3h 30m gap is not.
- Block 9:00 AM–1:30 PM IRST as the recurring meeting window if you work primarily from IRST and need WIB 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 WIB (Western Indonesia Time)
Western Indonesia Time (WIB, Waktu Indonesia Barat) is one of Indonesia's three time zones, fixed at UTC+07:00 all year. It covers Java, Sumatra, West Kalimantan and the provinces around them — home to Jakarta, the country's capital and largest city, plus Surabaya and Bandung. Indonesia does not observe daylight saving time, so WIB never shifts. WIB shares its UTC+07:00 offset with Indochina Time (ICT) and Christmas Island Time, but is a distinct zone covering the western half of the Indonesian archipelago. The country's other zones are WITA (UTC+08:00) in the centre and WIT (UTC+09:00) in the east.
Best time to call between IRST and WIB
Both IRST and WIB sit inside the 9 AM – 5 PM working day between 9:00 AM–1:30 PM IRST, which is 12:30 PM–5:00 PM WIB. That gives roughly 4 hours and 30 minutes of shared time — the safest window for a live call or meeting.
Business hours overlap
IRST and WIB overlap for about 4 hours during the working day — enough for meetings if you avoid the edges of the window.
IRST is 3 hours 30 minutes ahead of WIB (IRST UTC+03:30 → WIB UTC+07:00). The shared working window is 9:00 AM–1:30 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 WIB?
IRST (IRST, UTC+03:30) is 3 hours 30 minutes ahead of WIB (WIB, UTC+07:00). The gap is currently +3h 30m.
How do I convert IRST time to WIB time?
Add +3h 30m to IRST local time. For example, 9:00 AM in IRST is 12:30 PM in WIB.
What time is it in WIB right now?
WIB uses WIB at UTC+07:00. Use the live converter at the top of this page — it updates in real time and already accounts for the +3h 30m offset from IRST.
What is the best time to call WIB from IRST?
Call between 9:00 AM and 1:30 PM IRST — that maps to 12:30 PM–5:00 PM WIB and keeps both parties inside the working day.
Which is ahead, IRST or WIB?
IRST is 3 hours 30 minutes ahead of WIB. When it is 12:00 PM in IRST it is 3:30 PM in WIB.
Does daylight saving time affect the IRST–WIB difference?
Neither zone observes daylight saving time, so the +3h 30m offset between IRST and WIB 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 WIB?
Not normally. The +3h 30m gap only pushes the date over for late-evening times.
What is the time difference between IRST and WIB?
WIB is +3h 30m from IRST.
What timezone is IRST in?
IRST operates on its local timezone.
What timezone is WIB in?
WIB 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 WIB timezone?
Major cities in the WIB timezone include Jakarta, Surabaya, Bandung, Medan, Palembang.
What is the UTC offset for WIB?
Western Indonesia Time (WIB) is at UTC+07:00.
What should I know about the WIB timezone?
Indonesia spans three time zones: WIB (UTC+07:00), WITA (UTC+08:00) and WIT (UTC+09:00). Indonesia has not observed daylight saving time since 1964.
When is it midnight in IRST, what time is it in WIB?
When it is 12:00 AM (midnight) in IRST (IRST), it is +3h 30m later in WIB (WIB).
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