IST to GMT Converter
Enter an India time and date to read it in GMT, the UTC+0 reference. Neither side uses daylight saving here, so the answer never shifts with the season.
GMTGreenwich Mean Time
––:––
| IST time | GMT time |
|---|---|
| 12:00 AM | 6:30 PM−1 previous day |
| 1:00 AM | 7:30 PM−1 previous day |
| 2:00 AM | 8:30 PM−1 previous day |
| 3:00 AM | 9:30 PM−1 previous day |
| 4:00 AM | 10:30 PM−1 previous day |
| 5:00 AM | 11:30 PM−1 previous day |
| 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 | 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 |
A fixed 5 h 30 min gap
India Standard Time is UTC+5:30 and has no daylight saving. On this site GMT means the fixed UTC+0 reference, the same reading as Coordinated Universal Time, which the BIPM computes from atomic clocks around the world. Because neither side moves, the table above is valid for every date.
The half hour comes from geography. India's reference meridian is 82.5° east of Greenwich, and the Earth turns one degree every four minutes: 82.5 × 4 = 330 minutes, or 5 h 30 min.
- +5:30IST offset from GMT, all year
- 82.5° EIndia's reference meridian
- 0Clock changes per year in India
GMT is not always London time
Many people say GMT when they mean the time in London. That is right only from late October to late March. In summer the UK switches to British Summer Time, UTC+1, as listed by GOV.UK, and the gap to India shrinks to 4 h 30 min.
If your contact is in the UK, use the London clock, which follows the clock changes. If you need a fixed reference for logs, flight plans or broadcast schedules, GMT or UTC to IST is the right choice.
Check what GMT means in an invite
A UK colleague writing 3:00 PM GMT in July almost always means 3:00 PM London time, which is BST.
- Fixed GMT 3:00 PM = 8:30 PM IST.
- London 3:00 PM in summer = 7:30 PM IST.
- Ask for a city when the season matters.
Other ways to use the India offset
The same 5:30 rule works for any zone once you know its UTC offset. India is 4 h 30 min ahead of Central European Time in winter, and 2 h 30 min behind Singapore all year.
IST to GMT questions
How many hours is India ahead of GMT?
India is 5 hours 30 minutes ahead of GMT throughout the year. Subtract 5:30 from IST to get GMT.
What is 12:00 PM IST in GMT?
12:00 PM IST is 6:30 AM GMT on the same day.
Is GMT the same as UK time?
Only in winter. From late March to late October the UK is on British Summer Time, UTC+1, and London is then 4 h 30 min behind India.
Is IST ahead of UTC by the same amount?
Yes. GMT and UTC share the same clock reading for everyday purposes, so IST is UTC+5:30.
Why does India use a half-hour offset?
India's standard time is based on the 82.5° east meridian, and each degree of longitude is worth four minutes of time, which gives 5 hours 30 minutes.