GMT to IST
+4h 30mGMT
GMTSOURCEIST
ISTGreen rows indicate typical business hours (9 AM - 5 PM)
GMT and IST on the World Map
The map below highlights the GMT (Greenwich Mean Time) and IST (India Standard Time) timezone regions across the globe.
GMT – Greenwich Mean Time
UTC+00:00Greenwich Mean Time (GMT) is the mean solar time at the Royal Observatory in Greenwich, London. It is the same as UTC+00:00.
- •GMT is based on the Prime Meridian (0° longitude) passing through Greenwich, London.
- •The Royal Observatory in Greenwich has been the reference point for GMT since 1884.
- •GMT and UTC are often used interchangeably, but UTC is based on atomic clocks.
- •Iceland uses GMT year-round and never observes daylight saving time.
- •The UK switches from GMT to BST (British Summer Time) in late March each year.
IST – India Standard Time
UTC+05:30India Standard Time (IST) is the time zone for India and Sri Lanka, 5 hours and 30 minutes ahead of UTC.
- •India is 10 hours 30 minutes ahead of EST and 5 hours 30 minutes ahead of GMT.
- •India uses a single time zone despite spanning 30° of longitude.
- •IST is one of only a handful of time zones with a 30-minute offset.
- •IST is the most populous single time zone in the world with over 1.4 billion people.
- •The Bombay Stock Exchange (BSE) and National Stock Exchange (NSE) operate on IST.
GMT to IST Time Difference – Complete Guide
GMT (Greenwich Mean Time) operates on the Greenwich Mean Time (UTC+00:00). IST (India Standard Time) uses India Standard Time (UTC+05:30).
The time difference between GMT and IST is 270 minutes (+4h 30m). When it's noon in GMT, it's 04:30 PM in IST.
Why Convert GMT to IST Time?
Navigating the time gap between GMT and IST requires careful planning. With a difference of 4.5 hours, finding a suitable time for both locations is essential for effective collaboration. This tool simplifies the process, allowing you to instantly see the corresponding time in IST.
Remember: Daylight Saving Time changes can affect the time difference between GMT and IST. Always double-check the current offset before scheduling important events.
About GMT (Greenwich Mean Time)
Greenwich Mean Time (GMT) is the clock time at the Royal Observatory in Greenwich, London, which sits on the Prime Meridian (0° longitude). GMT serves as the reference point from which all other time zones are calculated. The United Kingdom uses GMT during winter months and switches to British Summer Time (BST, UTC+01:00) from late March to late October. Several West African nations use GMT year-round. GMT is often used interchangeably with UTC (Coordinated Universal Time), although technically they are different – UTC is based on atomic clocks while GMT is based on Earth's rotation.
About IST (India Standard Time)
India Standard Time (IST) is the time observed throughout India and Sri Lanka. It is based on the 82.5°E meridian, passing through Mirzapur in Uttar Pradesh. India uses a single time zone despite spanning roughly 30° of longitude, which has been debated. IST does not observe daylight saving time. India is the world's most populous country, making IST one of the most-used time zones globally. The IT outsourcing industry and call centers operate primarily on IST, making the EST-to-IST conversion one of the most searched timezone conversions.
Best Time to Call Between GMT and IST
If you want to reach someone in IST during standard business hours (9 AM – 5 PM IST), the best time to call from GMT would be:
- IST 9:00 AM = GMT 04:30 AM
- IST 12:00 PM = GMT 07:30 AM
- IST 5:00 PM = GMT 12:30 PM
Business Hours Overlap
GMT and IST have a partial business hours overlap. The best window for meetings and calls is when both locations are in their working hours.
Ultimately, understanding the +4h 30m difference between GMT and IST empowers you to coordinate better. Whether for business or personal reasons, this tool ensures you're always on time.
🕐 Daylight Saving Time Info
GMT
☀ Currently in DST
Standard: UTC+00:00 · DST: UTC+01:00
Clocks fall back on Sun, Oct 25, 2026
IST
Does not observe DST
Learn More About Time
Dive deeper into the fascinating world of timekeeping, time zones, and how they shape our global society:
Frequently Asked Questions
What is the time difference between GMT and IST?
IST is +4h 30m from GMT.
What timezone is GMT in?
GMT operates on its local timezone.
What timezone is IST in?
IST operates on its local timezone.
Which countries use GMT (Greenwich Mean Time)?
GMT is used in United Kingdom, Ireland, Iceland, Portugal (mainland), Ghana, Senegal, and 9 more countries.
Does GMT observe daylight saving time?
Yes, GMT switches to BST during summer months.
What are some interesting facts about GMT?
GMT is based on the Prime Meridian (0° longitude) passing through Greenwich, London. The Royal Observatory in Greenwich has been the reference point for GMT since 1884.
Which cities are in the IST timezone?
Major cities in the IST timezone include Mumbai, Delhi, Bangalore, Kolkata, Chennai, Hyderabad, Pune, Ahmedabad.
What is the UTC offset for IST?
India Standard Time (IST) is at UTC+05:30.
What should I know about the IST timezone?
India is 10 hours 30 minutes ahead of EST and 5 hours 30 minutes ahead of GMT. India uses a single time zone despite spanning 30° of longitude.
When is it midnight in GMT, what time is it in IST?
When it is 12:00 AM (midnight) in GMT (GMT), it is +4h 30m later in IST (IST).
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