🇬🇧
UK British Summer Time (BST) — How GMT/BST Changes the IST Gap
The United Kingdom observes Daylight Saving Time in the form of British Summer Time (BST). Clocks go forward 1 hour in late March and back in late October. Because India's IST (UTC+5:30) is fixed, London moves 1 hour closer to IST during BST, shrinking the typical 5.5-hour gap to 4.5 hours.
Standard time
GMT (UTC+0)
Greenwich Mean Time
⟷
DST / Summer time
BST (UTC+1)
British Summer Time
IST gap (standard)
5h 30m behind IST
→
IST gap (DST)
4h 30m behind IST
Clock Change Schedule
Clocks spring forward 1 hour on the **last Sunday of March** at 1 AM, switching GMT→BST. They fall back on the **last Sunday of October** at 2 AM, switching BST→GMT. BST runs for approximately 7 months (late March to late October).
2025
| Spring forward (GMT to BST) | 30 March 2025 |
| Fall back (BST to GMT) | 26 October 2025 |
2026
| Spring forward (GMT to BST) | 29 March 2026 |
| Fall back (BST to GMT) | 25 October 2026 |
United Kingdom Cities — IST Time Difference
How the IST gap changes for each United Kingdom city between standard and DST
| City | Time Zone | IST gap (GMT / standard) | IST gap (BST / summer) |
|---|---|---|---|
| London | GMT/BST | 5h 30m behind | 4h 30m behind |
| Edinburgh | GMT/BST | 5h 30m behind | 4h 30m behind |
| Dublin | GMT/IST (Irish) | 5h 30m behind | 4h 30m behind |
IST to GMT/BST Quick Reference
Both standard (GMT) and summer (BST) conversions at a glance
| IST (India) | GMT (standard, winter) | BST (summer) |
|---|---|---|
| 9:00 AM | 3:30 AM | 4:30 AM |
| 12:00 PM | 6:30 AM | 7:30 AM |
| 2:00 PM | 8:30 AM | 9:30 AM |
| 5:00 PM | 11:30 AM | 12:30 PM |
| 8:00 PM | 2:30 PM | 3:30 PM |
| 11:00 PM | 5:30 PM | 6:30 PM |
Current United Kingdom Time vs IST
India (IST)
--:--:--
loading…
United Kingdom (GMT/BST)
--:--:--
Frequently Asked Questions
What is the IST to GMT time difference?
IST (UTC+5:30) is 5 hours 30 minutes ahead of GMT (UTC+0). When it is 12:00 PM IST, it is 6:30 AM GMT in London. This offset applies from late October to late March.
What is the IST to BST time difference?
IST is 4 hours 30 minutes ahead of BST (UTC+1). When it is 12:00 PM IST, it is 7:30 AM BST in London. BST applies from the last Sunday of March to the last Sunday of October.
Is the gap between IST and London always 5.5 hours?
No. The gap is 5 hours 30 minutes when the UK is on GMT (winter, late October–late March) and 4 hours 30 minutes when on BST (summer, late March–late October). For the majority of the calendar year London is on BST.
Does Ireland change clocks at the same time as the UK?
Yes. Ireland observes Irish Standard Time (IST — confusingly the same abbreviation as Indian Standard Time) which runs from late March to late October, matching BST exactly. Ireland and the UK change clocks on the same day.
What is the overlap for Indo-UK business calls?
During GMT: India's 9 AM–6 PM IST corresponds to 3:30 AM–12:30 PM London time. Useful overlap window: roughly 2:30 PM–6:00 PM IST (9–12:30 in London). During BST: India 2:30 PM IST = 10 AM London, giving a wider practical morning overlap for London-side calling.