ISTtoGMTIndia Standard Time to Greenwich Mean Time
IST
India Standard Time (GMT+5:30)GMT
Greenwich Mean Time (GMT)Mutual Working Window: 2 Overlapping Hours
Recommended calling window between IST and GMT
Both locations share 2 overlapping standard business hours (9:00 AM – 5:00 PM). This is the premier window for real-time video conferences, corporate calls, and instant collaboration without outside-hours disruption.
24-Hour Schedule Conversion Matrix
Compare every hour of the day between IST and GMT.
| IST Time (India Standard Time) | GMT Time (Greenwich Mean Time) | Status & Recommendation |
|---|---|---|
| 00:00AM | 18:00PM-1 day | ⚪ Outside Work Hours |
| 01:00AM | 19:00PM-1 day | ⚪ Outside Work Hours |
| 02:00AM | 20:00PM-1 day | ⚪ Outside Work Hours |
| 03:00AM | 21:00PM-1 day | ⚪ Outside Work Hours |
| 04:00AM | 22:00PM-1 day | ⚪ Outside Work Hours |
| 05:00AM | 23:00PM-1 day | ⚪ Outside Work Hours |
| 06:00AM | 00:00AM | ⚪ Outside Work Hours |
| 07:00AM | 01:00AM | ⚪ Outside Work Hours |
| 08:00AM | 02:00AM | ⚪ Outside Work Hours |
| 09:00AM | 03:00AM | ⚪ Outside Work Hours |
| 10:00AM | 04:00AM | ⚪ Outside Work Hours |
| 11:00AM | 05:00AM | ⚪ Outside Work Hours |
| 12:00PM | 06:00AM | ⚪ Outside Work Hours |
| 13:00PM | 07:00AM | 🟡 Feasible (Shoulder Hour) |
| 14:00PM | 08:00AM | 🟡 Feasible (Shoulder Hour) |
| 15:00PM | 09:00AM | 🟢 Ideal Meeting Window |
| 16:00PM | 10:00AM | 🟢 Ideal Meeting Window |
| 17:00PM | 11:00AM | ⚪ Outside Work Hours |
| 18:00PM | 12:00PM | ⚪ Outside Work Hours |
| 19:00PM | 13:00PM | ⚪ Outside Work Hours |
| 20:00PM | 14:00PM | ⚪ Outside Work Hours |
| 21:00PM | 15:00PM | ⚪ Outside Work Hours |
| 22:00PM | 16:00PM | ⚪ Outside Work Hours |
| 23:00PM | 17:00PM | ⚪ Outside Work Hours |
Frequently Asked Questions
What is the time difference between IST and GMT?
GMT is 5 hours 30 minutes behind IST. When it is 12:00 PM (noon) in IST, the current synchronized time in GMT is 6:30 AM.
What are the overlapping working hours between IST and GMT?
There are 2 overlapping standard business hours (9:00 AM – 5:00 PM) between IST and GMT. The optimal scheduling window is 3:00 PM – 5:00 PM in IST (9:00 AM – 11:00 AM in GMT).
Does daylight saving time affect the conversion between IST and GMT?
Yes. GMT observes daylight saving shifts (BST), shifting the offset difference by 1 hour between summer and winter while IST stays on fixed standard time year-round.
What regions and major cities observe IST and GMT?
IST (India Standard Time) is primarily observed across South Asia (Republic of India & Sri Lanka) (key hubs include New Delhi, Mumbai, Bengaluru, Hyderabad). GMT (Greenwich Mean Time) is observed across Western Europe & West Africa (United Kingdom, Ireland, Portugal, Ghana) (key hubs include London, Dublin, Lisbon, Accra).
What is 9:00 AM IST in GMT?
9:00 AM in IST corresponds to 3:30 AM in GMT. You can cross-reference every hour of the day in the 24-hour visual schedule table above.
Which time zone is ahead, IST or GMT?
IST is ahead by 5 hours and 30 minutes.