Convert IRST to GST
GST is 30 minutes ahead of IRST. IRST is UTC+3:30 and GST is UTC+4.
Right now: IRST · GST
Best time to schedule a meeting
Standard 9–5 working hours overlap for 8 hours: 9:00 AM–5:00 PM IRST (9:00 AM–5:00 PM GST). Schedule meetings inside that window.
| IRST | GST | Suitable? |
|---|---|---|
| 9:00 AM | 9:30 AM | working hours |
| 10:00 AM | 10:30 AM | working hours |
| 11:00 AM | 11:30 AM | working hours |
| 12:00 PM | 12:30 PM | working hours |
| 1:00 PM | 1:30 PM | working hours |
| 2:00 PM | 2:30 PM | working hours |
| 3:00 PM | 3:30 PM | working hours |
| 4:00 PM | 4:30 PM | working hours |
| 5:00 PM | 5:30 PM | outside 9–5 |
IRST to GST conversion table
| IRST | GST |
|---|---|
| 12:00 AM | 12:30 AM |
| 1:00 AM | 1:30 AM |
| 2:00 AM | 2:30 AM |
| 3:00 AM | 3:30 AM |
| 4:00 AM | 4:30 AM |
| 5:00 AM | 5:30 AM |
| 6:00 AM | 6:30 AM |
| 7:00 AM | 7:30 AM |
| 8:00 AM | 8:30 AM |
| 9:00 AM | 9:30 AM |
| 10:00 AM | 10:30 AM |
| 11:00 AM | 11:30 AM |
| 12:00 PM | 12:30 PM |
| 1:00 PM | 1:30 PM |
| 2:00 PM | 2:30 PM |
| 3:00 PM | 3:30 PM |
| 4:00 PM | 4:30 PM |
| 5:00 PM | 5:30 PM |
| 6:00 PM | 6:30 PM |
| 7:00 PM | 7:30 PM |
| 8:00 PM | 8:30 PM |
| 9:00 PM | 9:30 PM |
| 10:00 PM | 10:30 PM |
| 11:00 PM | 11:30 PM |
About IRST
Iran Standard Time (IRST) is UTC+3:30. It is used in Iran, all year.
Iran Standard Time is UTC+3:30. Iran ran daylight saving for decades and stopped in 2022, so material written before then puts the country half an hour further ahead in summer and is now wrong. Half-hour offsets are rare enough that scheduling tools sometimes round them, which turns a correct calculation into a thirty-minute error.
About GST
Gulf Standard Time (GST) is UTC+4. It is used in Dubai, Abu Dhabi and Muscat.
Gulf Standard Time is UTC+4, covering the United Arab Emirates and Oman, and there is no daylight saving anywhere on the Arabian peninsula. The scheduling complication in the region is not the clock but the week: the UAE moved its weekend to Saturday–Sunday in 2022, while Saudi Arabia and several neighbours keep Friday–Saturday, so a Thursday afternoon meeting lands differently across a border that has no time difference at all.
Does this gap change with the seasons?
Neither IRST nor GST shifts with the seasons, so this 0.5-hour difference holds all year. That is unusual enough to be worth relying on: most cross-continental gaps move twice a year.
This is the reason scheduling systems store an IANA zone such as Region/City rather than an offset or an abbreviation: the zone knows its own rules and the offset does not.
Frequently asked questions
What time is 9:00 AM IRST in GST?
9:00 AM IRST is 9:30 AM GST.
Is GST ahead of IRST?
GST is 30 minutes ahead of IRST.
Which time zone does this use?
IRST is UTC+3:30 and GST is UTC+4. Both abbreviations denote a single fixed offset, so this conversion never shifts with daylight saving — what changes is which abbreviation a place is using at the time.