Compare IST and GMT
See the current IST to GMT time difference, understand DST impacts, and find the best hours to schedule calls or meetings.
How to Find the Time Difference Between IST and GMT
Open the IST vs GMT converter: Go to https://www.xconvert.com/time-converter/ist-vs-gmt to load a comparison grid with IST (India Standard Time) and GMT (Greenwich Mean Time) already shown as separate rows. This page is useful when you are scheduling a client call between India and the UK, planning a support handoff between a Bengaluru engineering team and a London operations team, or checking whether a shipment update from Mumbai will arrive during UK office hours.
Add other relevant cities with “+ Add City”: Click “+ Add City” and search for cities such as London, Dubai, or New York to compare IST and GMT against major business hubs. London matters because many finance, legal, and consulting teams work on UK time; Dubai is a common trade and aviation link for India-bound travel; and New York helps global teams see whether a meeting that works for GMT also overlaps with US market hours.
Drag across the grid to select a meeting window: Click “Select” if needed, then drag across the IST row from 9:00 AM to 11:00 AM IST to create a purple highlighted range with draggable handles. That selection shows 3:30 AM to 5:30 AM GMT, which makes it clear that a standard India morning meeting is too early for UK participants; if you instead drag 2:00 PM to 5:00 PM IST, you get 8:30 AM to 11:30 AM GMT, a much more practical overlap for remote team coordination and customer calls.
Export or share the selected time range: After selecting a range, use the export options for ICS download, Google Calendar, Gmail, Copy to clipboard, or Share link. This is especially useful if you need to send a confirmed cross-border meeting to a distributed team, create a calendar event that automatically converts to each attendee’s local time, or quickly paste the overlap into email for a UK-India project kickoff.
IST vs GMT Offset Explained
IST is UTC+5:30, while GMT is UTC+0:00, so IST is exactly 5 hours 30 minutes ahead of GMT year-round. That means when it is 9:00 AM in IST, it is 3:30 AM in GMT, and when it is 6:00 PM in IST, it is 12:30 PM in GMT. This half-hour offset is important because many people assume all major time zones differ by full hours, but India uses a fixed offset based on 82.5°E longitude, centered near Mirzapur, Uttar Pradesh.
India Standard Time does not observe daylight saving time at any point in the year. GMT also remains UTC+0:00 and does not change seasonally, so the IST-GMT difference stays a constant +5:30 in every month, including January, June, and December. This makes IST vs GMT simpler than IST vs UK local civil time, because the UK often uses British Summer Time (BST, UTC+1) instead of GMT during part of the year.
The seasonal confusion usually comes from mixing GMT with London time. In the UK, daylight saving time for 2026 begins on 29 March 2026, when clocks move forward from 1:00 AM GMT to 2:00 AM BST, and ends on 25 October 2026, when clocks move back from 2:00 AM BST to 1:00 AM GMT. During that BST period, IST is only 4 hours 30 minutes ahead of London local time, not 5 hours 30 minutes, so a 2:00 PM IST meeting corresponds to 9:30 AM in London during summer but 8:30 AM GMT during winter.
This distinction matters for real scheduling decisions in outsourcing, finance, aviation, and software delivery. India’s large technology and business-process centers in Bengaluru, Hyderabad, Pune, Chennai, Gurugram, and Mumbai often work with UK-based clients in banking, insurance, consulting, and e-commerce. If a team schedules by “GMT” when they actually mean “London time,” they can be off by one hour for roughly seven months of the year, which can affect standups, production releases, and trading-related coordination.
Frequently Asked Questions
What is the exact time difference between IST and GMT?
IST is 5 hours 30 minutes ahead of GMT. For example, 12:00 noon GMT is 5:30 PM IST, and 8:00 AM IST is 2:30 AM GMT. Because neither IST nor GMT changes seasonally, this difference stays fixed all year.
Is IST always 5 hours 30 minutes ahead of GMT?
Yes, IST is always +5:30 relative to GMT because India does not use daylight saving time and GMT itself remains at UTC+0:00. The only common source of confusion is when people compare IST to UK local time in summer, which is usually BST (UTC+1) rather than GMT.
Why does IST have a 30-minute offset instead of a full hour?
India uses UTC+5:30 as a single national standard time based on the country’s central reference meridian at 82.5° east longitude. This was adopted to provide one uniform time across a geographically wide country of over 1.4 billion people, including major metros such as Delhi, Mumbai, Kolkata, Chennai, and Bengaluru. The half-hour offset helps align solar time more reasonably across India than a strict full-hour alternative would.
Does GMT change with daylight saving time?
No, GMT itself does not observe daylight saving time and remains UTC+0:00 throughout the year. However, the UK often switches to British Summer Time (BST, UTC+1) from late March to late October, so if you are scheduling with someone in London, you must confirm whether they mean GMT or current UK local time.
What is the best meeting time overlap between IST and GMT for work calls?
A practical overlap for same-day business calls is usually 1:30 PM to 6:00 PM IST, which corresponds to 8:00 AM to 12:30 PM GMT. This window works well for UK morning meetings and India afternoon sessions, making it common for software delivery reviews, customer support escalations, and consulting check-ins. Earlier IST morning slots usually fall before UK business hours, while late GMT afternoons push India into evening.
How do I convert IST to GMT quickly?
Subtract 5 hours 30 minutes from IST to get GMT. For example, 7:30 PM IST becomes 2:00 PM GMT, and 10:00 AM IST becomes 4:30 AM GMT. On the xconvert grid, you can visually drag a range on the IST row and instantly see the corresponding GMT hours without doing manual math.
Is London the same as GMT all year?
No, London is not the same as GMT all year. London uses GMT in winter and BST (UTC+1) in summer, so for part of the year London is one hour ahead of GMT. This matters for travel planning, financial market coordination, and international interviews, because a meeting labeled “London time” may not match GMT between late March and late October.
When should India and GMT teams avoid scheduling meetings?
Teams should usually avoid early IST mornings because they fall in the middle of the night in GMT, and avoid late GMT afternoons because they push Indian participants into late evening. For example, 9:00 AM IST is only 3:30 AM GMT, while 5:00 PM GMT is already 10:30 PM IST. That makes midday IST and morning GMT the most sustainable overlap for recurring meetings.