GMT to GST Time Converter
GST is 3 hours ahead of GMT. The UK and Ireland are currently on BST (UTC+1:00), and GST is UTC+4:00.
Best Time to Call Between GMT and GST
Both zones are inside normal business hours between 9:00 AM and 2:00 PM GMT — that's 12:00 PM to 5:00 PM GST. That's a 5-hour window.
both at work GMT only GST only neither — hours along the strip are GMT.
Common Times Converted
GMT on the left, GST on the right.
GMT to GST: Full 24-Hour Conversion Table
Shaded rows are working hours; the darker shade marks the hours when both zones are at work.
| GMT | GST | Working hours |
|---|---|---|
| 12:00 AM | 3:00 AM | — |
| 1:00 AM | 4:00 AM | — |
| 2:00 AM | 5:00 AM | — |
| 3:00 AM | 6:00 AM | — |
| 4:00 AM | 7:00 AM | — |
| 5:00 AM | 8:00 AM | — |
| 6:00 AM | 9:00 AM | GST only |
| 7:00 AM | 10:00 AM | GST only |
| 8:00 AM | 11:00 AM | GST only |
| 9:00 AM | 12:00 PM | Both zones |
| 10:00 AM | 1:00 PM | Both zones |
| 11:00 AM | 2:00 PM | Both zones |
| 12:00 PM | 3:00 PM | Both zones |
| 1:00 PM | 4:00 PM | Both zones |
| 2:00 PM | 5:00 PM | GMT only |
| 3:00 PM | 6:00 PM | GMT only |
| 4:00 PM | 7:00 PM | GMT only |
| 5:00 PM | 8:00 PM | — |
| 6:00 PM | 9:00 PM | — |
| 7:00 PM | 10:00 PM | — |
| 8:00 PM | 11:00 PM | — |
| 9:00 PM | 12:00 AM next day | — |
| 10:00 PM | 1:00 AM next day | — |
| 11:00 PM | 2:00 AM next day | — |
What GMT and GST Actually Are
GMT — Greenwich Mean Time
The UK and Ireland in winter, plus Iceland, Portugal and much of West Africa. Standing at UTC as written, and the region does change its clocks, so its live offset moves by an hour twice a year. The next change is on Sunday, October 25, 2026, to GMT. Often used loosely as a synonym for UTC. They differ by less than a second, so for scheduling they are interchangeable.
Britain ran an experiment from 1968 to 1971 on permanent UTC+1, abandoning GMT entirely. It was scrapped after complaints about dark winter mornings in Scotland.
GST — Gulf Standard Time
Dubai, Abu Dhabi, Sharjah, Muscat. Standing at UTC+4:00 as written, and the region does not change its clocks, so that offset holds all year. GST also refers to South Georgia Time (UTC-2), which you are very unlikely to want.
The Gulf states have never observed daylight saving, so Dubai's offset has been unchanged for decades — unusual stability for a region that grew as fast as it did.
What This Means in Practice
This gap is not fixed
GMT changes its clocks and GST does not, so the difference between them moves by an hour twice a year. A recurring meeting set now will drift for one side from Sunday, October 25, 2026 unless someone resets it.
Major Cities in Each Zone
Cities on GMT
Cities on GST
Frequently Asked Questions
What is the time difference between GMT and GST?
GST is 3 hours ahead of GMT. That is the live figure. Taken strictly as written, the gap between GMT and GST is 4 hours — the two differ because at least one of these regions is currently on daylight saving.
What is 9:00 AM GMT in GST?
9:00 AM GMT is 12:00 PM GST.
What are the best hours to schedule a call between GMT and GST?
Between 9:00 AM and 2:00 PM GMT, which is 12:00 PM to 5:00 PM GST. Both sides are inside normal business hours through that window.
Does the difference between GMT and GST change during the year?
Yes. GMT observes daylight saving and GST does not, so the gap shifts by an hour at least twice a year. The next clock change is on Sunday, October 25, 2026.
Does GMT always mean Greenwich Mean Time?
Often used loosely as a synonym for UTC. They differ by less than a second, so for scheduling they are interchangeable.
Does GST always mean Gulf Standard Time?
GST also refers to South Georgia Time (UTC-2), which you are very unlikely to want.