Conversion Updated: July 19, 2026

Time Conversion Calculator

GMT to IST Converter

Convert GMT to India Standard Time with date-aware logic, a 24-hour table, meeting planner, and copy-ready result.

Typical differenceIST is 5:30 aheadFixed-offset conversion for the selected date.

Convert GMT to IST

Choose a date and time in GMT. The calculator will show the matching India Standard Time time.

Conversion basis
Date-aware GMTUses UTC rules for the selected date.
India Standard Time resultThe target offset is calculated from the exact converted instant.
Choose a date and time to convert.
Converted IST time--India Standard Time
Time difference--Compared with GMT
GMT offset----
IST offset----
Copy-ready inviteConvert a time to build an invite snippet.

Suggested meeting times

Suggested meeting windowPick a suggested time or drag the bar.The third timeline row follows your auto-detected or searched timezone.

Timeline visualizer

Drag any row to move the meeting time. Green marks business hours, yellow marks daylight edges, and dark blue marks night.

Selected time--
Business hours Daylight edge Night Current time

24-hour GMT to IST conversion table

Full-day conversion for the selected date.

GMTIndia Standard TimeMeeting note
Select a time and convert to generate the table.
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GMT to IST: quick answer

To convert Greenwich Mean Time (GMT) to Indian Standard Time (IST), add 5 hours and 30 minutes. For example, 9:00 AM GMT is 2:30 PM IST on the same date. GMT is fixed at UTC+0 and IST is fixed at UTC+5:30, so the difference remains the same throughout the year.

Important: a time labelled “London time” may be GMT or British Summer Time (BST) depending on the date. This calculator converts fixed GMT, not seasonal London civil time.

How to convert GMT to IST

IST = GMT + 5 hours 30 minutes

  1. Start with the GMT date and time.
  2. Add five hours.
  3. Add another 30 minutes.
  4. If the result passes midnight, move to the next calendar date.

Example: 4:45 PM GMT + 5 hours 30 minutes = 10:15 PM IST. For 10:00 PM GMT, the result is 3:30 AM IST on the following date.

Common GMT to IST conversions

GMTISTDate note
12:00 AM5:30 AMSame date
6:00 AM11:30 AMSame date
9:00 AM2:30 PMSame date
12:00 PM5:30 PMSame date
3:00 PM8:30 PMSame date
6:00 PM11:30 PMSame date
7:00 PM12:30 AMNext date
10:00 PM3:30 AMNext date

GMT versus current UK time

GMT always means UTC+0. The United Kingdom uses GMT in winter and BST (UTC+1) in summer. Therefore, fixed GMT is always 5 hours 30 minutes behind IST, while current London time is either 5 hours 30 minutes or 4 hours 30 minutes behind IST depending on the selected date.

SourceOffsetAdd to reach IST
GMTUTC+05 hours 30 minutes
London on GMTUTC+05 hours 30 minutes
London on BSTUTC+14 hours 30 minutes

When the calendar date changes

GMT times from 6:30 PM through 11:59 PM convert to the following calendar date in IST. For example, 8:00 PM GMT on July 19 equals 1:30 AM IST on July 20. At exactly 6:30 PM GMT, the IST result is midnight on the next date.

Best GMT to IST meeting times

A practical fixed-GMT meeting window is 9:00 AM–1:00 PM GMT, corresponding to 2:30 PM–6:30 PM IST. This keeps the meeting within typical working hours in India. For participants physically located in the UK, check whether their selected date uses GMT or BST.

Formula, precision and verification

The converter treats GMT as UTC+00:00 and IST as UTC+05:30. It converts the entered GMT date and time to an exact instant, applies the fixed IST offset and displays the correct target date. No daylight-saving adjustment is added to either fixed standard.

  • Formula tested: IST = GMT + 05:30.
  • Boundary tests: 6:29 PM, 6:30 PM, midnight, noon and 11:59 PM GMT.
  • Date tests: next-date rollovers and month/year boundaries.
  • Cross-check: outputs compared with UTC arithmetic and configured offsets.
  • Last reviewed: July 19, 2026 by the CalculatorGeek Algorithmic Team.

Frequently asked questions

What is the time difference between GMT and IST?

IST is exactly 5 hours and 30 minutes ahead of GMT. This fixed difference does not change during the year.

What is 9 AM GMT in IST?

9:00 AM GMT is 2:30 PM IST on the same date.

What is 12 PM GMT in IST?

12:00 PM GMT is 5:30 PM IST on the same date.

What is 8 PM GMT in IST?

8:00 PM GMT is 1:30 AM IST on the following calendar date.

Is GMT the same as London time?

Only when the UK is observing GMT. London observes BST (UTC+1) during the summer period, so a London-time conversion must use the selected date.

How do I convert GMT to IST manually?

Add 5 hours and 30 minutes to GMT. If the result passes midnight, use the next calendar date.

Related converters and references

Authoritative references: IANA Time Zone Database, BIPM time metrology, CSIR–National Physical Laboratory India, and UK clock-change guidance.