IST to GMT Converter – Convert Indian Time to GMT
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Complete IST ↔ GMT Conversion Table
All 24 hours · Both DST seasons · Best meeting windows marked ★
| IST Time | GMT Time UTC+5:30 → UTC+0 (−5h 30m, constant) |
|---|---|
| 12:00 AM (midnight) | prev 6:30 PM |
| 1:00 AM | prev 7:30 PM |
| 2:00 AM | prev 8:30 PM |
| 3:00 AM | prev 9:30 PM |
| 4:00 AM | prev 10:30 PM |
| 5:00 AM | prev 11:30 PM |
| 6:00 AM | 12:30 AM |
| 7:00 AM | 1:30 AM |
| 8:00 AM | 2:30 AM |
| 9:00 AM | 3:30 AM |
| 10:00 AM | 4:30 AM |
| 11:00 AM | 5:30 AM |
| 12:00 PM (noon) | 6:30 AM |
| 1:00 PM | 7:30 AM |
| 2:00 PM | 8:30 AM |
| ★ 3:00 PM | ★ 9:30 AM |
| ★ 4:00 PM | ★ 10:30 AM |
| 5:00 PM | 11:30 AM |
| 6:00 PM | 12:30 PM |
| 7:00 PM | 1:30 PM |
| 8:00 PM | 2:30 PM |
| 9:00 PM | 3:30 PM |
| 10:00 PM | 4:30 PM |
| 11:00 PM | 5:30 PM |
What is the time difference between IST and GMT?
GMT is 5 hours 30 minutes behind IST. During late March to late October, when GMT switches to BST, the difference becomes 4 hours 30 minutes behind. 9:00 AM IST = 3:30 AM GMT. 12:00 PM IST = 6:30 AM GMT. 5:00 PM IST = 11:30 AM GMT.
What is the best time to call from Mumbai to London?
The business hours overlap between IST and GMT runs from 2:30 PM to 5:00 PM IST (9:00 AM to 11:30 AM GMT). Scheduling calls in this window keeps both sides within normal working hours.
Frequently Asked Questions about IST and GMT
GMT is 5 hours 30 minutes behind IST, so to convert mentally, subtract 5 hours 30 minutes to your IST time. For example: 9:00 AM IST = 3:30 AM GMT. Our converter automatically adjusts for Daylight Saving Time so you always get the right result.
GMT (Greenwich Mean Time, UTC+0) is 5 hours 30 minutes behind IST (India Standard Time, UTC+5:30) during standard time. For example, 9:00 AM IST = 3:30 AM GMT. During DST periods, this difference changes by 1 hour when one or both zones observe Daylight Saving Time - our converter automatically applies the correct offset for any date you select.
The best overlap for standard business hours (9 AM–5 PM) in both zones is 14:30–17:00 IST = 09:00–11:30 GMT. Schedule recurring calls in this window to keep both sides within normal working hours. Remember to re-check the window in March and November (or March/October for European zones) when DST transitions can shift the overlap by 1 hour.
India does not observe Daylight Saving Time. IST remains constant year-round, which simplifies conversions.
Major cities in the IST (India Standard Time, UTC+5:30) timezone include: Mumbai, New Delhi, Bangalore, Chennai, Kolkata, Hyderabad, Pune. IST is a fixed-offset zone - these cities do not observe Daylight Saving Time.
Major cities in the GMT (Greenwich Mean Time, UTC+0) timezone include: London (winter), Dublin (winter), Edinburgh, Reykjavik, Accra, Dakar. These cities switch to BST (UTC+1) from the last Sunday in March to the last Sunday in October.
GMT is 5 hours 30 minutes behind IST. The best overlap for business hours is 14:30–17:00 IST = 09:00–11:30 GMT. Always include both local times in calendar invites (for example, "2:00 PM IST / 8:30 AM GMT GMT"). Double-check around March and November (or March/October for European zones) when DST transitions can shift the offset by 1 hour. For full scheduling guidance, see our international meeting times guide.
Need more help? Check our complete FAQ section.
View Complete FAQPopular Cities in These Timezones
IST Timezone Cities:
Mumbai, Delhi, Bangalore, Kolkata
GMT Timezone Cities:
London, Dublin, Edinburgh, Cardiff