Convert IRST to SGT
SGT is 4 hours 30 minutes ahead of IRST. IRST is UTC+3:30 and SGT is UTC+8.
Right now: IRST · SGT
Best time to schedule a meeting
Standard 9–5 working hours overlap for 4 hours: 9:00 AM–1:00 PM IRST (1:00 PM–5:00 PM SGT). Schedule meetings inside that window.
| IRST | SGT | Suitable? |
|---|---|---|
| 9:00 AM | 1:30 PM | working hours |
| 10:00 AM | 2:30 PM | working hours |
| 11:00 AM | 3:30 PM | working hours |
| 12:00 PM | 4:30 PM | working hours |
| 1:00 PM | 5:30 PM | outside 9–5 |
| 2:00 PM | 6:30 PM | outside 9–5 |
| 3:00 PM | 7:30 PM | outside 9–5 |
| 4:00 PM | 8:30 PM | outside 9–5 |
| 5:00 PM | 9:30 PM | outside 9–5 |
IRST to SGT conversion table
| IRST | SGT |
|---|---|
| 12:00 AM | 4:30 AM |
| 1:00 AM | 5:30 AM |
| 2:00 AM | 6:30 AM |
| 3:00 AM | 7:30 AM |
| 4:00 AM | 8:30 AM |
| 5:00 AM | 9:30 AM |
| 6:00 AM | 10:30 AM |
| 7:00 AM | 11:30 AM |
| 8:00 AM | 12:30 PM |
| 9:00 AM | 1:30 PM |
| 10:00 AM | 2:30 PM |
| 11:00 AM | 3:30 PM |
| 12:00 PM | 4:30 PM |
| 1:00 PM | 5:30 PM |
| 2:00 PM | 6:30 PM |
| 3:00 PM | 7:30 PM |
| 4:00 PM | 8:30 PM |
| 5:00 PM | 9:30 PM |
| 6:00 PM | 10:30 PM |
| 7:00 PM | 11:30 PM |
| 8:00 PM | 12:30 AM (next day) |
| 9:00 PM | 1:30 AM (next day) |
| 10:00 PM | 2:30 AM (next day) |
| 11:00 PM | 3:30 AM (next day) |
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 SGT
Singapore Time (SGT) is UTC+8. It is used in Singapore and Malaysia.
Singapore Time is UTC+8 with no daylight saving. The offset is a historical curiosity: Singapore sits at about 104°E, which is geographically UTC+7, and moved to +8 in 1982 to align with Malaysia and Hong Kong for trade. The result is that the sun is at its highest around 1pm rather than noon, and sunrise is late all year.
Does this gap change with the seasons?
Neither IRST nor SGT shifts with the seasons, so this 4.5-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 SGT?
9:00 AM IRST is 1:30 PM SGT.
Is SGT ahead of IRST?
SGT is 4 hours 30 minutes ahead of IRST.
Which time zone does this use?
IRST is UTC+3:30 and SGT is UTC+8. 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.