MeetingHours

GMT to IST

New Delhi is 4½ hours ahead of London at the moment — this pair shifts across the year.

GMT now IST now Network measuring…

GMT and IST across the year

The difference is not a single number. In July, New Delhi is 4½ hours ahead of London; in January it is 5½ hours ahead. That 1 hour swing happens because the two zones do not change their clocks together — and it is why a recurring meeting set once will quietly move for one side after a changeover.

GMT: The UK is on GMT in winter and BST (UTC+1) in summer, so 'GMT' and 'London time' are the same thing for only half the year. Strictly, GMT never shifts — if you need a fixed reference, use UTC.

IST: IST means India Standard Time (UTC+5:30), Irish Standard Time (UTC+1) and Israel Standard Time (UTC+2). This page uses India, which is what the overwhelming majority of searches intend. India does not observe daylight saving, so the offset never changes.

GMT to IST at a glance

Working-hours conversions, using the July relationship. The live converter above always reflects today.

GMT — LondonIST — New Delhi
8:00 am12:30 pm
9:00 am1:30 pm
10:00 am2:30 pm
11:00 am3:30 pm
12:00 pm4:30 pm
1:00 pm5:30 pm
2:00 pm6:30 pm
3:00 pm7:30 pm
4:00 pm8:30 pm
5:00 pm9:30 pm

Scheduling between London and New Delhi

The workable window is 9:00 am to 2:00 pm in London — 1:30 pm to 6:30 pm in New Delhi. That is 5 hours out of a nine-hour working day, and everything outside it costs somebody their morning or their evening.

5 hours is a comfortable overlap; you can schedule inside it without much negotiation. The useful habit is still to put the New Delhi time in the invitation body as well as relying on the calendar to convert, because the person reading it on a phone will trust what they can see.

The two edges behave differently. Booking at 9:00 am London time means New Delhi is late in its afternoon and may be winding down; booking at 1:00 pm means London is mid-afternoon while New Delhi is closer to the end of the day. Where the decision matters, give the later-in-the-day side the earlier slot.

If you are the one in London

New Delhi is ahead of you, which means their day is already ending as yours gets going. By the time you are at your desk at 9:00 am, it is 1:30 pm there — so anything you send in your morning arrives in their afternoon, with time to act on it. The practical consequence is that your late afternoon is dead time for anything needing a reply from New Delhi: they are asleep, and you will not hear back until your next morning.

So the discipline that pays off is front-loading. Anything New Delhi needs from you should go out early in your day while they are still working; anything you need from them should be asked for before you leave, so it is waiting when you return. Treat their evening as the deadline, not yours.

If this is a recurring meeting, create it with real time zones — a calendar invitation tied to "London" rather than to a fixed offset. Both zones' changeovers then take care of themselves. An invitation created as a bare UTC offset will drift by an hour twice a year and nobody will notice until somebody misses a call.

Related conversions

EST → GMTGMT → ESTPST → GMTEST → ISTIST → ESTPST → ISTUTC → IST

Plan across more than two cities at once →

Questions

What time is GMT in IST?
IST is 4½ hours ahead of GMT in July, and 5½ hours ahead of it in January — the gap changes across the year because at least one of the two observes daylight saving. The converter above uses whichever relationship applies today.
Is the difference between GMT and IST the same all year?
No. It is 4½ hours in July and 5½ hours in January. If you are scheduling something recurring — a weekly call, a standing meeting — it will drift by an hour at each daylight-saving changeover unless the invitation was created with real time zones rather than a fixed offset.
What is the best time to schedule a call between London and New Delhi?
Between 9:00 am and 2:00 pm in London, which is 1:30 pm to 6:30 pm in New Delhi. That is 5 hours of genuine overlap and it is the only part of the day that costs neither side anything.
Does IST mean something else?
IST means India Standard Time (UTC+5:30), Irish Standard Time (UTC+1) and Israel Standard Time (UTC+2). This page uses India, which is what the overwhelming majority of searches intend. India does not observe daylight saving, so the offset never changes.