IST to GMT converter
GMT is 5 hours 30 minutes behind India Standard Time year-round: India Standard Time runs at UTC+5:30 and GMT at UTC+0. To convert IST to GMT, subtract 5 hours 30 minutes from the IST time. Neither zone observes daylight saving time, so the offsets hold on every date.
India Standard Time runs at UTC+5:30, GMT at UTC+0.
IST to GMT conversion table
Every hour of the day converted. One column is enough here: the gap between the two zones is the same in winter and summer.
| India Standard Time (IST) | GMT (GMT) |
|---|---|
| 00:00 12:00 AM | 18:30 6:30 PM previous day |
| 01:00 1:00 AM | 19:30 7:30 PM previous day |
| 02:00 2:00 AM | 20:30 8:30 PM previous day |
| 03:00 3:00 AM | 21:30 9:30 PM previous day |
| 04:00 4:00 AM | 22:30 10:30 PM previous day |
| 05:00 5:00 AM | 23:30 11:30 PM previous day |
| 06:00 6:00 AM | 00:30 12:30 AM |
| 07:00 7:00 AM | 01:30 1:30 AM |
| 08:00 8:00 AM | 02:30 2:30 AM |
| 09:00 9:00 AM | 03:30 3:30 AM |
| 10:00 10:00 AM | 04:30 4:30 AM |
| 11:00 11:00 AM | 05:30 5:30 AM |
| 12:00 12:00 PM | 06:30 6:30 AM |
| 13:00 1:00 PM | 07:30 7:30 AM |
| 14:00 2:00 PM | 08:30 8:30 AM |
| 15:00 3:00 PM | 09:30 9:30 AM |
| 16:00 4:00 PM | 10:30 10:30 AM |
| 17:00 5:00 PM | 11:30 11:30 AM |
| 18:00 6:00 PM | 12:30 12:30 PM |
| 19:00 7:00 PM | 13:30 1:30 PM |
| 20:00 8:00 PM | 14:30 2:30 PM |
| 21:00 9:00 PM | 15:30 3:30 PM |
| 22:00 10:00 PM | 16:30 4:30 PM |
| 23:00 11:00 PM | 17:30 5:30 PM |
How the IST to GMT conversion works
Converting IST to GMT means taking a wall-clock time in India Standard Time (IST, UTC+5:30) and expressing the same instant in GMT (GMT, UTC+0). The arithmetic is one step: subtract 5 hours 30 minutes from any IST time, and it holds on every date of the year. Applying the gap pushes part of the day onto a different calendar date — the table below marks every row that shifts. In code, store the instant in UTC and convert with the IANA identifiers Asia/Kolkata and Etc/GMT, never with the abbreviations. One note on the source label: IST is also used for Irish Standard Time and Israel Standard Time, so the abbreviation alone is ambiguous. IANA identifiers carry the full offset history of a region, including every daylight saving transition ever legislated, which is why databases, schedulers, and APIs should store them.
GMT vs UTC
GMT on this page names the fixed Etc/GMT zone, which is identical to UTC+0 every day of the year — the table above is exact regardless of which term you use. It is not the same thing as UK local time: the United Kingdom itself keeps GMT only from late October to late March and observes British Summer Time (UTC+1) the rest of the year, one hour ahead of every GMT value on this page. If your search for GMT meant the UK's current clock rather than the fixed reference offset, check which side of that switch today falls on.
Meant the fixed reference rather than UK local time? IST to UTC reports the same numbers under that name.
Best time for meetings between IST and GMT
Working hours are taken as 09:00–18:00 in each zone. The window in force depends on the date, so both halves of the year are listed where they differ.
GMT, year-round
A 9-to-6 working day in both zones overlaps for 3 hours 30 minutes: 2:30 PM–6:00 PM IST is 9:00 AM–12:30 PM GMT. Book inside that window and neither side is working outside normal hours.
Daylight saving time: which side moves
Neither India Standard Time nor GMT observes daylight saving time, so the difference stays at 5 hours 30 minutes year-round. There is no transition weekend to plan around, and neither zone has a summer abbreviation.
- India Standard Time
- Asia/Kolkata
- IST — UTC+5:30
- GMT
- Etc/GMT
- GMT — UTC+0
Frequently asked questions
What is the time difference between IST and GMT?
GMT runs 5 hours 30 minutes behind India Standard Time on every date of the year. In offset terms, India Standard Time sits at UTC+5:30 and GMT at UTC+0. So 9:00 AM IST is 3:30 AM GMT. The hour-by-hour table on this page lists the conversion for all 24 hours so you do not have to do the arithmetic.
Does the IST to GMT difference change with daylight saving time?
The difference is fixed at 5 hours 30 minutes. Neither India Standard Time nor GMT observes daylight saving time, so no date in the calendar changes the conversion. GMT here is the fixed UTC+0 standard; the United Kingdom itself leaves GMT for BST (UTC+1) each summer. Convert against the IANA rules for the exact date rather than a remembered offset.
What time is 9 am IST in GMT?
9:00 AM IST is 3:30 AM in GMT, and it stays that way all year because the two zones stay 5 hours 30 minutes apart. The rule is the same one the whole page runs on: subtract 5 hours 30 minutes from any IST time. Check the hour-by-hour table for any other starting hour, including the rows that land on the previous or next calendar day.
What do IST and GMT stand for?
IST stands for India Standard Time. GMT stands for Greenwich Mean Time. Both are display labels rather than rules: the offsets behind them come from the IANA identifiers Asia/Kolkata and Etc/GMT. IST is also used for Irish Standard Time and Israel Standard Time, so the abbreviation alone is ambiguous. GMT is fixed at UTC+0 as a time standard, but people often write it when they mean UK local time, which becomes BST in summer.
Related conversions
Need more than two zones at once? The full timezone converter shows a single moment across up to six IANA timezones, for any date you choose.