IST to WIB Time Converter
WIB is 1 hour and 30 minutes ahead of IST. IST is UTC+5:30, and WIB is UTC+7:00.
Best Time to Call Between IST and WIB
Both zones are inside normal business hours between 9:00 AM and 4:00 PM IST — that's 10:30 AM to 5:30 PM WIB. That's a 7-hour window.
both at work IST only WIB only neither — hours along the strip are IST.
Common Times Converted
IST on the left, WIB on the right.
IST to WIB: Full 24-Hour Conversion Table
Shaded rows are working hours; the darker shade marks the hours when both zones are at work.
| IST | WIB | Working hours |
|---|---|---|
| 12:00 AM | 1:30 AM | — |
| 1:00 AM | 2:30 AM | — |
| 2:00 AM | 3:30 AM | — |
| 3:00 AM | 4:30 AM | — |
| 4:00 AM | 5:30 AM | — |
| 5:00 AM | 6:30 AM | — |
| 6:00 AM | 7:30 AM | — |
| 7:00 AM | 8:30 AM | — |
| 8:00 AM | 9:30 AM | WIB only |
| 9:00 AM | 10:30 AM | Both zones |
| 10:00 AM | 11:30 AM | Both zones |
| 11:00 AM | 12:30 PM | Both zones |
| 12:00 PM | 1:30 PM | Both zones |
| 1:00 PM | 2:30 PM | Both zones |
| 2:00 PM | 3:30 PM | Both zones |
| 3:00 PM | 4:30 PM | Both zones |
| 4:00 PM | 5:30 PM | IST only |
| 5:00 PM | 6:30 PM | — |
| 6:00 PM | 7:30 PM | — |
| 7:00 PM | 8:30 PM | — |
| 8:00 PM | 9:30 PM | — |
| 9:00 PM | 10:30 PM | — |
| 10:00 PM | 11:30 PM | — |
| 11:00 PM | 12:30 AM next day | — |
What IST and WIB Actually Are
IST — India Standard Time
Mumbai, Delhi, Bengaluru, Chennai, Kolkata, Hyderabad — and Colombo. Standing at UTC+5:30 as written, and the region does not change its clocks, so that offset holds all year. IST also stands for Irish Standard Time (UTC+1) and Israel Standard Time (UTC+2). This page covers the Indian one, which is by far the most searched.
India runs a single time zone across a country wide enough for two, which is why sunrise in the north-east can come nearly two hours before Mumbai's. Proposals for a second zone resurface regularly and have never been adopted.
WIB — Western Indonesian Time
Jakarta, Surabaya, Bandung, Medan. Standing at UTC+7:00 as written, and the region does not change its clocks, so that offset holds all year. Indonesia spans three zones: WIB (UTC+7), WITA (UTC+8) and WIT (UTC+9).
Indonesia spans three time zones. A long-running proposal to unify the country onto a single clock has repeatedly stalled.
What This Means in Practice
Expect times on the half hour
IST sits on a 30-minute offset rather than a whole hour, so a round number on one side is never a round number on the other. A 9:00 meeting becomes 30 minutes past the hour, which is exactly the detail calendar invitations get wrong when someone converts in their head.
A gap you can rely on
Neither region changes its clocks, so this difference holds every day of the year. A recurring meeting booked once stays correct — worth knowing, because most cross-border pairs cannot say that.
Close enough to share a working day
At only 1 hour and 30 minutes apart, the two working days overlap almost completely. Scheduling is barely constrained by the difference.
Major Cities in Each Zone
Cities on IST
Cities on WIB
Frequently Asked Questions
What is the time difference between IST and WIB?
WIB is 1 hour and 30 minutes ahead of IST.
What is 9:00 AM IST in WIB?
9:00 AM IST is 10:30 AM WIB.
What are the best hours to schedule a call between IST and WIB?
Between 9:00 AM and 4:00 PM IST, which is 10:30 AM to 5:30 PM WIB. Both sides are inside normal business hours through that window.
Does the difference between IST and WIB change during the year?
No. Neither region changes its clocks, so this gap is fixed all year round.
Does IST always mean India Standard Time?
IST also stands for Irish Standard Time (UTC+1) and Israel Standard Time (UTC+2). This page covers the Indian one, which is by far the most searched.
Does WIB always mean Western Indonesian Time?
Indonesia spans three zones: WIB (UTC+7), WITA (UTC+8) and WIT (UTC+9).