GMT to IST Converter
IST is 5 hours 30 minutes ahead of GMT. During UK BST (summer), the gap narrows to 4 hours 30 minutes.
Daylight saving note: During UK BST (late March–late October), the gap narrows from 5h 30m to 4h 30m. India never observes DST.
GMT to IST Conversion Table
Full 24-hour reference table. Use the live clocks above for the exact current offset.
| 🇬🇧 GMT | 🇮🇳 GMT → ISTUTC+0 to UTC+5:30 | 🇮🇳 BST → ISTUTC+1 to UTC+5:30 | Note |
|---|---|---|---|
| 00:00 | 5:30 AM | 4:30 AM | |
| 01:00 | 6:30 AM | 5:30 AM | |
| 02:00 | 7:30 AM | 6:30 AM | |
| 03:00 | 8:30 AM | 7:30 AM | |
| 04:00 | 9:30 AM | 8:30 AM | |
| 05:00 | 10:30 AM | 9:30 AM | |
| 06:00 | 11:30 AM | 10:30 AM | |
| 07:00 | 12:30 PM | 11:30 AM | |
| 08:00 | 1:30 PM | 12:30 PM | |
| 09:00 | 2:30 PM | 1:30 PM | |
| 10:00 | 3:30 PM | 2:30 PM | |
| 11:00 | 4:30 PM | 3:30 PM | |
| 12:00 | 5:30 PM | 4:30 PM | |
| 13:00 | 6:30 PM | 5:30 PM | |
| 14:00 | 7:30 PM | 6:30 PM | |
| 15:00 | 8:30 PM | 7:30 PM | |
| 16:00 | 9:30 PM | 8:30 PM | |
| 17:00 | 10:30 PM | 9:30 PM | |
| 18:00 | 11:30 PM | 10:30 PM | |
| 19:00 | 12:30 AM | 11:30 PM | next day |
| 20:00 | 1:30 AM | 12:30 AM | next day |
| 21:00 | 2:30 AM | 1:30 AM | next day |
| 22:00 | 3:30 AM | 2:30 AM | next day |
| 23:00 | 4:30 AM | 3:30 AM | next day |
* "next day" = converted time falls on the following calendar day.
Best Hours to Schedule Greenwich Mean Time–India Standard Time Calls
London–India has the most comfortable overlap of any major Western city. London's 9:00 AM GMT = 2:30 PM IST. The full morning in London (9 AM–1:30 PM GMT) aligns with India's afternoon (2:30–7:00 PM IST) — giving both teams a solid half-day to collaborate.
About Greenwich Mean Time (GMT)
Greenwich Mean Time (GMT, UTC+0) is the UK's winter timezone. From late March to late October, the UK switches to BST (British Summer Time, UTC+1), narrowing the gap with India. London is the starting point of the global timezone system — the GMT meridian runs through Greenwich.
About India Standard Time (IST)
India Standard Time (IST, UTC+5:30) sits 5.5 hours ahead of GMT. This is a more workable gap than the US-India difference — UK teams can hold morning calls that land during India's afternoon. The UK-India corridor is one of the strongest bilateral IT relationships, with over £42 billion in annual trade.
How to Avoid Greenwich Mean Time–India Standard Time Conversion Mistakes
Use the live clocks and the table for different jobs. The live clocks show the current offset between Greenwich Mean Time and India Standard Time. The table gives you a stable reference for planning common hours. If the page has more than one table column, pick the column that matches the season or DST state shown in the column label.
Daylight saving is the main trap. Some pairs stay fixed all year, while others move by one hour because only one side changes clocks, or because the two sides change on different dates. That is why this page keeps the daylight saving note near the live clocks and labels alternate table scenarios instead of hiding the offset change in a paragraph.
Always check the calendar date when the converted time lands near midnight. A late evening time in Greenwich Mean Time can become the next day in India Standard Time, and an early morning time can still be the previous day. If the table marks "next day" or "prev day", include that date shift in the message or calendar invite.
Abbreviations can be ambiguous. ET can mean EST or EDT; London can be GMT or BST; Sydney can be AEST or AEDT. City names and IANA time zones are safer for exact scheduling than abbreviations alone. For recurring meetings, test the same local time once in January and once in July before you lock it in.
For one-off events, enter the exact date and time in the main time zone converter or meeting scheduler if the table does not show your hour. That keeps the answer tied to the correct daylight saving rule instead of a memorized offset.
When you share the result, write both local times in one line: "10:00 AM GMT/ converted IST time." For client calls, flights, webinars, launches, and deadlines, also include the date. The extra wording feels repetitive, but it gives every recipient a second way to catch a timezone mistake before it becomes a missed meeting. It is especially helpful when someone forwards the invite to a third city.
Frequently Asked Questions
What is the GMT to IST time difference?
IST is 5 hours 30 minutes ahead of GMT. During UK BST (late March–late October), the gap is 4 hours 30 minutes. India does not change its clocks.
What time is 9 AM GMT in IST?
9:00 AM GMT is 2:30 PM IST. During UK BST, 9:00 AM BST is 1:30 PM IST. The half-hour component of IST (UTC+5:30) always adds :30 to any round-hour GMT time.
Why does India have a half-hour timezone offset?
India set UTC+5:30 in 1905 to create a single timezone for the whole subcontinent. The longitude of India's geographic centre falls at ~82.5°E, corresponding to UTC+5:30. This half-hour offset has remained since.
What is the best time for a UK-India call?
The best window is 9:00 AM–1:30 PM GMT (2:30–7:00 PM IST). This gives London a full morning and India a comfortable afternoon. After 1:30 PM London, India starts entering evening hours.