What is the time difference between GMT and IST?

India Standard Time (IST) is 4 hours and 30 minutes ahead of Greenwich Mean Time (GMT). GMT uses a UTC offset of UTC+1, while IST uses UTC+5:30. For example, when it's 9:00 AM in GMT, it's 1:30 PM in IST. Note that this difference may shift by one hour during daylight saving time transitions if GMT observes DST. Use the conversion table above to see the exact time for each hour of the day.

How do I convert GMT to IST?

To convert GMT to IST, add 4 hours and 30 minutes to the GMT time. For example, 9:00 AM GMT is 1:30 PM IST, and 5:00 PM GMT is 9:30 PM IST. Keep in mind that during daylight saving time transitions, the offset between these timezones may temporarily change by one hour. You can also use the interactive converter above for quick, accurate results.

What time is it in IST when it's noon in GMT?

When it's 12:00 PM (noon) in GMT, it's 4:30 PM in IST. This is because IST is 4 hours and 30 minutes ahead of GMT. Similarly, when it's 6:00 PM in GMT, it's 10:30 PM in IST. During daylight saving time transitions, these times may shift by one hour, so always verify the current offset. The color-coded conversion table above shows every hour mapped between both timezones.

How many hours ahead is IST from GMT?

IST is 4 hours and 30 minutes ahead of GMT. This means when it's 9:00 AM in GMT, it's 1:30 PM in IST, and when it's midnight in GMT, it's 4:30 AM in IST. The exact difference can vary by one hour during daylight saving time transitions. The conversion table above provides a complete hour-by-hour mapping.

Is IST ahead or behind GMT?

IST is ahead of GMT by 4 hours and 30 minutes. Clocks in IST show a later time than GMT, meaning the day starts earlier in IST relative to GMT. For example, when it's morning in GMT, it's later in the morning in IST. This gap may change by one hour during DST transitions.

Does GMT observe daylight saving time?

Yes, Greenwich Mean Time observes daylight saving time. During DST, the abbreviation changes to BST and clocks move forward by one hour, typically in spring. Clocks then fall back in autumn, returning to standard GMT time. This means the UTC offset for GMT shifts between two values depending on the season. Check our DST change calendar for exact transition dates that may affect your GMT to IST conversions.

Does IST observe daylight saving time?

No, India Standard Time does not observe daylight saving time. The UTC offset of UTC+5:30 remains the same year-round, making time conversions to IST more predictable. Countries and regions in this timezone keep their clocks unchanged regardless of the season.

What is the best time to call from GMT to IST?

The best time for a call between GMT and IST is during overlapping business hours (9 AM – 5 PM) in both timezones. To reach someone in IST during their work day, call between 4:30 AM and 12:30 PM your GMT time. Avoid calling too early or late, as the 4 hours and 30 minutes difference means your evening could be their late night. Check the color-coded conversion table above — green hours indicate business hours in both zones, making it easy to find the ideal time.

When does daylight saving time change in GMT?

Daylight saving time transitions vary by year and region. Greenwich Mean Time observes DST, which typically shifts clocks forward by one hour in spring ("spring forward") and back in fall ("fall back"). During these transition periods, the time difference between GMT and IST may temporarily change by one hour, which can cause confusion for scheduled meetings or calls. It's important to double-check your conversions around transition dates, especially if the two timezones switch on different dates. Check our DST change calendar for exact transition dates in the current year.

Do GMT and IST ever have the same time?

No, GMT and IST never show the same time because their base UTC offsets are different. However, because GMT observes daylight saving time and IST does not, the time difference between them changes by one hour during DST transitions. This means the gap narrows or widens depending on the season, but the two clocks never align. Always verify the current offset around DST transition dates to avoid scheduling errors.

GMT to IST Converter

Convert Greenwich Mean Time to India Standard Time. See the hour-by-hour conversion table below.

Timezone Details

Greenwich Mean Time

2:42 AM

Friday, April 3, 2026

BST (UTC+01:00)

India Standard Time

7:12 AM

Friday, April 3, 2026

IST (UTC+05:30)

Difference: +4h 30m

BST DST: Yes (BST)

IST DST: No

24-Hour Overview

BST — 24-hour overview

12a12a

3a3a

6a6a

9a9a

10a

11a

12p12p

3p3p

6p6p

9p9p

10p

11p

NightMorningBusinessEvening

IST — 24-hour overview

4a4a

7a7a

10a10a

11a

12p

1p1p

4p4p

7p7p

10p10p

11p

12a

1a1a

NightMorningBusinessEvening

Frequently Asked Questions

Related Conversions

IST to GMT EST to GMT GMT to EST EST to IST IST to EST PST to GMT GMT to PST PST to IST IST to PST

Cities in These Timezones

GMT Cities

London Manchester Edinburgh

IST Cities

Delhi Mumbai Kolkata Bangalore Chennai

More Tools

Compare GMT & IST Plan a Meeting (GMT & IST)See on Map

Learn More

How Time Zones Work Understanding DST Timezone Abbreviations

External Resources

Greenwich Mean Time on Wikipedia India Standard Time on Wikipedia IANA Time Zone Database