Convert BST to IST
IST = BST +4 h 30 min
IST is 4 hours 30 minutes ahead of BST. BST is always UTC+1 and IST is always UTC+5:30, so this gap is the same on every date.
BST · British Summer Time · UTC+1
1:14PM
Tuesday, November 3, 2026
IST · India Standard Time · UTC+5:30
5:44PM
Tuesday, November 3, 2026
The UK is on GMT (UTC+0) right now.
- Next clock change: March 28, 2027. The UK moves to BST (UTC+1), so India is then 4 hours 30 minutes ahead of the UK.
- Next clock change: October 31, 2027. The UK moves to GMT (UTC+0), so India is then 5 hours 30 minutes ahead of the UK.
BST to IST for every hour
Each IST column holds for part of the year (dates in the header for 2027). The first uses the fixed offsets (BST UTC+1, IST UTC+5:30); the others give local clock time when daylight saving time changes the gap. From 7:30 PM BST, IST is already on the next calendar day.
| BST | IST +4 h 30 minfixed offsets | IST +5 h 30 minJan 1 – Mar 28, Oct 31 – Dec 31 | 24-hour |
|---|---|---|---|
| 12:00 AM | 4:30 AM | 5:30 AM | 00:00 → 04:30 |
| 1:00 AM | 5:30 AM | 6:30 AM | 01:00 → 05:30 |
| 2:00 AM | 6:30 AM | 7:30 AM | 02:00 → 06:30 |
| 3:00 AM | 7:30 AM | 8:30 AM | 03:00 → 07:30 |
| 4:00 AM | 8:30 AM | 9:30 AM | 04:00 → 08:30 |
| 5:00 AM | 9:30 AM | 10:30 AM | 05:00 → 09:30 |
| 6:00 AM | 10:30 AM | 11:30 AM | 06:00 → 10:30 |
| 7:00 AM | 11:30 AM | 12:30 PM | 07:00 → 11:30 |
| 8:00 AM | 12:30 PM | 1:30 PM | 08:00 → 12:30 |
| 9:00 AM | 1:30 PM | 2:30 PM | 09:00 → 13:30 |
| 10:00 AM | 2:30 PM | 3:30 PM | 10:00 → 14:30 |
| 11:00 AM | 3:30 PM | 4:30 PM | 11:00 → 15:30 |
| 12:00 PM | 4:30 PM | 5:30 PM | 12:00 → 16:30 |
| 1:00 PM | 5:30 PM | 6:30 PM | 13:00 → 17:30 |
| 2:00 PM | 6:30 PM | 7:30 PM | 14:00 → 18:30 |
| 3:00 PM | 7:30 PM | 8:30 PM | 15:00 → 19:30 |
| 4:00 PM | 8:30 PM | 9:30 PM | 16:00 → 20:30 |
| 5:00 PM | 9:30 PM | 10:30 PM | 17:00 → 21:30 |
| 6:00 PM | 10:30 PM | 11:30 PM | 18:00 → 22:30 |
| 7:00 PM | 11:30 PM | 12:30 AM +1 day | 19:00 → 23:30 |
| 8:00 PM | 12:30 AM +1 day | 1:30 AM +1 day | 20:00 → 00:30 |
| 9:00 PM | 1:30 AM +1 day | 2:30 AM +1 day | 21:00 → 01:30 |
| 10:00 PM | 2:30 AM +1 day | 3:30 AM +1 day | 22:00 → 02:30 |
| 11:00 PM | 3:30 AM +1 day | 4:30 AM +1 day | 23:00 → 03:30 |
Bold rows fall inside office hours (9:00 to 17:00) on both sides. The dot marks the current BST hour.
The BST times people look up most
| BST | IST +4 h 30 min | IST +5 h 30 min |
|---|---|---|
| 10:00 AM | 2:30 PM | 3:30 PM |
| 1:00 PM | 5:30 PM | 6:30 PM |
| 9:00 AM | 1:30 PM | 2:30 PM |
| 10:30 AM | 3:00 PM | 4:00 PM |
| 10:30 PM | 3:00 AM +1 day | 4:00 AM +1 day |
| 11:00 AM | 3:30 PM | 4:30 PM |
| 8:00 AM | 12:30 PM | 1:30 PM |
Does the difference change during the year?
As written, no: BST is always UTC+1 and IST is always UTC+5:30, so the gap is 4 hours 30 minutes on every date. But the UK uses BST only in summer, and people often keep writing “BST” when they mean the local time. Between the local clocks of the UK and India, the gap is 5 hours 30 minutes or 4 hours 30 minutes:
| From | What changes | The UK | India | IST vs BST |
|---|---|---|---|---|
| January 1 | Start of the year | GMT (UTC+0) | IST (UTC+5:30) | +5 h 30 min |
| March 29 | The UK moves to BST (UTC+1) | BST (UTC+1) | IST (UTC+5:30) | +4 h 30 min |
| October 25 | The UK moves to GMT (UTC+0) | GMT (UTC+0) | IST (UTC+5:30) | +5 h 30 min |
| From | What changes | The UK | India | IST vs BST |
|---|---|---|---|---|
| January 1 | Start of the year | GMT (UTC+0) | IST (UTC+5:30) | +5 h 30 min |
| March 28 | The UK moves to BST (UTC+1) | BST (UTC+1) | IST (UTC+5:30) | +4 h 30 min |
| October 31 | The UK moves to GMT (UTC+0) | GMT (UTC+0) | IST (UTC+5:30) | +5 h 30 min |
Converting BST to IST by hand
With the fixed offsets, add 4 hours 30 minutes: 3:30 PM BST is 8:00 PM IST.
With the +5 h 30 min gap (Jan 1 – Mar 28, Oct 31 – Dec 31), add 5 hours 30 minutes: 3:30 PM BST is 9:00 PM IST.
Going back from IST to BST, do the opposite: the IST to BST page has its own table.
Where the BST and IST working days overlap
BST to IST (+4 h 30 min): Two 9:00–17:00 days share 3 hours 30 minutes: 9:00 AM to 12:30 PM BST, which is 1:30 PM to 5:00 PM IST.
+5 h 30 min (from Jan 1 to Mar 28 and Oct 31 to Dec 31, 2027): Two 9:00–17:00 days share 2 hours 30 minutes: 9:00 AM to 11:30 AM BST, which is 2:30 PM to 5:00 PM IST.
A meeting fixed in one city’s calendar moves by an hour for the other when the gap changes. Calendar apps handle this when the event is saved in a named zone (for example Europe/London) rather than as a fixed offset.
What BST and IST mean
British Summer Time
BST is UTC+1, the UK’s summer time, from 1:00 AM GMT on the last Sunday of March to 1:00 AM GMT on the last Sunday of October (Summer Time Act 1972 as amended in 2002). In winter the UK is on GMT, UTC+0.
India Standard Time
IST here is India Standard Time, UTC+5:30, used in all of India all year: no daylight saving time and a single zone for the whole country.
IST can also mean Israel Standard Time (UTC+2, Israel) or Irish Standard Time (UTC+1, Ireland, in summer). This page uses India Standard Time, the meaning people searching for this conversion have in mind. For another one, type the city into the time zone converter.