GMT to IST conversion: India (IST, UTC+5:30) is 5 hours 30 minutes ahead of London when the UK is on Greenwich Mean Time and 4 hours 30 minutes ahead during British Summer Time (BST, UTC+1), from late March to late October. The converter below applies the right offset.
Uses your browser’s built-in time zone data (IANA tz database), so daylight saving is applied for the date you pick. Nothing you enter leaves your device.
GMT to IST offsets and 2026 switch dates
| Period (2026) | London zone | UTC offset | India (IST) is ahead by |
|---|---|---|---|
| 1 Jan – 29 March 2026 | GMT | UTC+0 | 5 h 30 min |
| 29 March 2026 – 25 October 2026 | BST | UTC+1 | 4 h 30 min |
| 25 October 2026 – 31 Dec | GMT | UTC+0 | 5 h 30 min |
Clocks in London go forward on Sunday 29 March 2026, 1:00 am GMT and back on Sunday 25 October 2026, 1:00 am GMT (2:00 am BST). The rule is the last Sunday in March to last Sunday in October at 01:00 GMT (Summer Time Order 2002); source: The Summer Time Order 2002, checked 9 October 2026 against the IANA time zone database. India does not use daylight saving: IST is UTC+5:30 all year.
India–London business hours overlap
India working day 09:00–18:00 IST, London working day 09:00–17:00 local time; working hours are in bold. Winter column uses GMT, summer column uses BST.
| IST (India) | London, GMT (winter) | London, BST (summer) |
|---|---|---|
| 07:00 | 01:30 | 02:30 |
| 08:00 | 02:30 | 03:30 |
| 09:00 | 03:30 | 04:30 |
| 10:00 | 04:30 | 05:30 |
| 11:00 | 05:30 | 06:30 |
| 12:00 | 06:30 | 07:30 |
| 13:00 | 07:30 | 08:30 |
| 14:00 | 08:30 | 09:30 |
| 15:00 | 09:30 | 10:30 |
| 16:00 | 10:30 | 11:30 |
| 17:00 | 11:30 | 12:30 |
| 18:00 | 12:30 | 13:30 |
| 19:00 | 13:30 | 14:30 |
| 20:00 | 14:30 | 15:30 |
| 21:00 | 15:30 | 16:30 |
| 22:00 | 16:30 | 17:30 |
| 23:00 | 17:30 | 18:30 |
Scheduling tips
- Always write meeting times with both zones, for example “19:00 IST / 09:30 BST”.
- On each switch date the gap to India changes by one hour; re-check recurring meetings that week.
- Calendar apps convert automatically if each invite carries a time zone; avoid typing times in the subject line only.
Share your result or suggest a fix
Did the converter show a time you did not expect? Email [email protected] with the date, both cities and what you expected; we check it against the IANA time zone database and note any correction with its date. Comments are switched off on this site.
FAQ
What is 12 noon GMT in IST?
5:30 pm IST. If London is on BST, 12 noon in London is 4:30 pm IST.
Is BST to IST different from GMT to IST?
Yes. BST is one hour ahead of GMT, so London is 4 h 30 min behind India during BST and 5 h 30 min behind during GMT.
Is UTC the same as GMT?
For everyday time conversion yes: both are UTC+0, so UTC to IST is also +5 h 30 min. The UK only differs when it switches to BST.
When do India and London office hours overlap?
With India working 9:00 to 18:00 IST and London 9:00 to 17:00, the overlap is 1:30 pm to 6:00 pm IST during BST and 2:30 pm to 6:00 pm IST during GMT.
Kalinga Times is an independent time tools site, not affiliated with the former Kalinga Times newspaper. Kalinga Times home.
Updated 9 October 2026 · Kalinga Times editorial team
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