Convert GMT to IST: Greenwich Mean Time to India Time
Converting Greenwich Mean Time (GMT) to Indian Standard Time (IST) is a daily need for anyone bridging Europe/Africa and India. The one thing to remember: India runs on a half-hour offset, UTC+5:30, and never changes it. That half hour is what catches people out.
Time Zone Overview
Greenwich Mean Time (GMT)
GMT is UTC+0 in winter. The UK switches to BST (UTC+1) in summer, so the reference point shifts.
Indian Standard Time (IST)
IST is UTC+5:30 all year. India does not observe daylight saving time, so the offset is fixed.
Time Difference
UK winter (GMT): India is 5 hours 30 minutes ahead of GMT.
UK summer (BST): India is 4 hours 30 minutes ahead of London.
Conversion Formula
IST = GMT + 5 hours 30 minutes (winter) / GMT + 4 hours 30 minutes (UK summer)
Conversion Examples
Winter: 9:00 GMT → 14:30 IST
Summer: 9:00 BST → 13:30 IST
Watch the half hour. 12:00 GMT is 17:30 IST, not 17:00.
Quick Reference Table (GMT → IST)
| GMT (London winter) | IST | BST (London summer) | IST |
|---|---|---|---|
| 6:00 AM | 11:30 AM | 6:00 AM | 10:30 AM |
| 9:00 AM | 2:30 PM | 9:00 AM | 1:30 PM |
| 12:00 PM | 5:30 PM | 12:00 PM | 4:30 PM |
| 3:00 PM | 8:30 PM | 3:00 PM | 7:30 PM |
| 6:00 PM | 11:30 PM | 6:00 PM | 10:30 PM |
| 9:00 PM | 2:30 AM (next day) | 9:00 PM | 1:30 AM (next day) |
Common Use Cases
- Outsourcing and IT team coordination between the UK and India
- Scheduling calls between London and Bangalore, Mumbai, or Delhi
- Tracking Indian market hours from Europe
- Family and personal calls across the regions
Frequently Asked Questions
What is the time difference between GMT and IST?
5 hours 30 minutes in UK winter, 4 hours 30 minutes in summer.
Why the half hour?
India deliberately uses UTC+5:30 and keeps it year-round.
If it's 9 AM GMT, what time is it in India?
2:30 PM IST (winter) or 1:30 PM IST (summer BST).
Does India observe DST?
No. IST is UTC+5:30 all year.
How do I convert IST to GMT?
Subtract 5h30m in winter or 4h30m in UK summer.
Use our world clock and meeting planner for date-specific planning.