Singapore to IRST
-4h 30mSingapore
SGTSOURCEIRST
IRSTGreen rows indicate typical business hours (9 AM - 5 PM)
SGT and IRST on the World Map
The map below highlights the SGT (Singapore Standard Time) and IRST (Iran Standard Time) timezone regions across the globe.
SGT – Singapore Standard Time
UTC+08:00Singapore Standard Time (SGT) is the time zone for Singapore, 8 hours ahead of UTC.
- •Singapore uses UTC+08:00 despite being at about 104°E longitude (closer to UTC+07:00).
- •Singapore does not observe daylight saving time.
- •The Singapore Exchange (SGX) operates on SGT.
IRST – Iran Standard Time
UTC+03:30Iran Standard Time (IRST) is the time zone for Iran, 3 hours and 30 minutes ahead of UTC.
- •IRST is one of only a few time zones with a 30-minute offset.
- •Iran observes daylight saving time, switching to IRDT (UTC+04:30).
- •Tehran has a metropolitan population of over 16 million.
About Singapore
WikipediaSingapore Standard Time (SGT) is 8 hours ahead of GMT. As Asia's leading financial hub, Singapore bridges business hours between Europe and Australia.
The city-state has the world's highest percentage of millionaires, with 1 in 6 households.
Understanding the -4h 30m Gap: Singapore vs IRST
Singapore runs on Singapore Standard Time (SGT) at UTC+08:00. IRST runs on Iran Standard Time (IRST) at UTC+03:30. That puts Singapore 4 hours 30 minutes behind IRST — a difference of -4h 30m at the current offsets.
In practice, when it is 9:00 AM in Singapore it is 4:30 AM in IRST. Midnight in Singapore is 7:30 PM in IRST. Neither zone observes daylight saving time, so the offset between them stays constant all year.
Singapore to IRST time conversion table
| Singapore (SGT) | IRST (IRST) | Day |
|---|---|---|
| 12:00 AM | 7:30 PM | previous day |
| 6:00 AM | 1:30 AM | same day |
| 7:00 AM | 2:30 AM | same day |
| 8:00 AM | 3:30 AM | same day |
| 9:00 AM | 4:30 AM | same day |
| 12:00 PM | 7:30 AM | same day |
| 3:00 PM | 10:30 AM | same day |
| 5:00 PM | 12:30 PM | same day |
| 6:00 PM | 1:30 PM | same day |
| 9:00 PM | 4:30 PM | same day |
Why people convert Singapore to IRST time
- Scheduling a call from Singapore to IRST: a 10:00 AM start in Singapore lands at 5:30 AM in IRST, so you can confirm the slot without doing the arithmetic yourself.
- Finding shared working hours: both Singapore and IRST are inside the 9-to-5 working day between 1:30 PM and 5:00 PM SGT time (9:00 AM–12:30 PM IRST). That is roughly 3 hours 30 minutes of usable overlap.
- Booking travel or deliveries: tracking IRST local time against Singapore keeps pickup windows and arrival estimates honest across the -4h 30m offset.
- Always state the zone abbreviation, not just the hour. "3:00 PM SGT" is unambiguous; "3 PM" across a -4h 30m gap is not.
- Block 1:30 PM–5:00 PM SGT as the recurring meeting window if you work primarily from Singapore and need IRST colleagues present.
About SGT (Singapore Standard Time)
Singapore Standard Time (SGT) is used in Singapore year-round. Singapore does not observe daylight saving time. Despite being geographically close to the UTC+07:00 zone, Singapore uses UTC+08:00 to align with major trading partners like China, Hong Kong, and Malaysia. Singapore is a major global financial hub.
About IRST (Iran Standard Time)
Iran Standard Time (IRST) is one of the few time zones with a 30-minute offset. Iran observes daylight saving time (IRDT, UTC+04:30) from late March to late September. Tehran, the capital, is one of the largest cities in the Middle East.
Best time to call between Singapore and IRST
Both Singapore and IRST sit inside the 9 AM – 5 PM working day between 1:30 PM–5:00 PM SGT, which is 9:00 AM–12:30 PM IRST. That gives roughly 3 hours and 30 minutes of shared time — the safest window for a live call or meeting.
Business hours overlap
Singapore and IRST overlap for about 3 hours during the working day — enough for meetings if you avoid the edges of the window.
Singapore is 4 hours 30 minutes behind IRST (SGT UTC+08:00 → IRST UTC+03:30). The shared working window is 1:30 PM–5:00 PM SGT. Remember to re-check around daylight-saving transitions.
Learn More About Time
Dive deeper into the fascinating world of timekeeping, time zones, and how they shape our global society:
Frequently Asked Questions
What is the time difference between Singapore and IRST?
Singapore (SGT, UTC+08:00) is 4 hours 30 minutes behind IRST (IRST, UTC+03:30). The gap is currently -4h 30m.
How do I convert Singapore time to IRST time?
Add -4h 30m to Singapore local time. For example, 9:00 AM in Singapore is 4:30 AM in IRST.
What time is it in IRST right now?
IRST uses IRST at UTC+03:30. Use the live converter at the top of this page — it updates in real time and already accounts for the -4h 30m offset from Singapore.
What is the best time to call IRST from Singapore?
Call between 1:30 PM and 5:00 PM SGT — that maps to 9:00 AM–12:30 PM IRST and keeps both parties inside the working day.
Which is behind, Singapore or IRST?
Singapore is 4 hours 30 minutes behind IRST. When it is 12:00 PM in Singapore it is 7:30 AM in IRST.
Do Singapore and IRST use different time zones?
Singapore (Singapore) uses SGT at UTC+08:00, while IRST uses IRST at UTC+03:30. The IANA identifiers are Asia/Singapore and Asia/Tehran.
Does daylight saving time affect the Singapore–IRST difference?
Neither zone observes daylight saving time, so the -4h 30m offset between Singapore and IRST is fixed all year.
Which other cities share Singapore's time zone?
SGT also covers Singapore.
Which countries use SGT, Singapore's zone?
SGT is used in Singapore.
Is there a day difference between Singapore and IRST?
Not normally. The -4h 30m gap only pushes the date over the previous day.
What is the time difference between Singapore and IRST?
IRST is -4h 30m from Singapore.
What timezone is Singapore in?
Singapore Standard Time (SGT) is 8 hours ahead of GMT. As Asia's leading financial hub, Singapore bridges business hours between Europe and Australia.
What timezone is IRST in?
IRST operates on its local timezone.
What are the business hours in Singapore?
Standard business hours in Singapore are 9:00 AM - 6:00 PM SGT.
Which countries use SGT (Singapore Standard Time)?
SGT is used in Singapore.
Does SGT observe daylight saving time?
No, SGT does not observe daylight saving time and remains at UTC+08:00 year-round.
What are some interesting facts about SGT?
Singapore uses UTC+08:00 despite being at about 104°E longitude (closer to UTC+07:00). Singapore does not observe daylight saving time.
Which cities are in the IRST timezone?
Major cities in the IRST timezone include Tehran, Isfahan, Mashhad, Tabriz, Shiraz, Karaj.
What is the UTC offset for IRST?
Iran Standard Time (IRST) is at UTC+03:30. During daylight saving time, it shifts to IRDT.
What should I know about the IRST timezone?
IRST is one of only a few time zones with a 30-minute offset. Iran observes daylight saving time, switching to IRDT (UTC+04:30).
When is it midnight in Singapore, what time is it in IRST?
When it is 12:00 AM (midnight) in Singapore (SGT), it is -4h 30m later in IRST (IRST).
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