SGT to Tehran
-4h 30mSGT
SGTSOURCETehran
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 Tehran
WikipediaTehran operates on Iran Standard Time (IRST), UTC+3:30. Iran's unique half-hour offset makes Tehran time distinctive for regional business coordination.
Iran Standard Time (IRST) is one of few timezones with a 30-minute offset (UTC+3:30).
SGT vs Tehran: Offsets, DST and Best Call Times
SGT runs on Singapore Standard Time (SGT) at UTC+08:00. Tehran runs on Iran Standard Time (IRST) at UTC+03:30. That puts SGT 4 hours 30 minutes behind Tehran — a difference of -4h 30m at the current offsets.
In practice, when it is 9:00 AM in SGT it is 4:30 AM in Tehran. Midnight in SGT is 7:30 PM in Tehran. Neither zone observes daylight saving time, so the offset between them stays constant all year.
SGT to Tehran time conversion table
| SGT (SGT) | Tehran (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 SGT to Tehran time
- Scheduling a call from SGT to Tehran: a 10:00 AM start in SGT lands at 5:30 AM in Tehran, so you can confirm the slot without doing the arithmetic yourself.
- Finding shared working hours: both SGT and Tehran 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.
- Keeping family and friends in sync: knowing that 8:00 PM in SGT is 3:30 PM in Tehran makes it easy to avoid calling at 3 AM.
- 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 SGT and need Tehran 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 SGT and Tehran
Both SGT and Tehran 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
SGT and Tehran overlap for about 3 hours during the working day — enough for meetings if you avoid the edges of the window.
SGT is 4 hours 30 minutes behind Tehran (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 SGT and Tehran?
SGT (SGT, UTC+08:00) is 4 hours 30 minutes behind Tehran (IRST, UTC+03:30). The gap is currently -4h 30m.
How do I convert SGT time to Tehran time?
Add -4h 30m to SGT local time. For example, 9:00 AM in SGT is 4:30 AM in Tehran.
What time is it in Tehran right now?
Tehran 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 SGT.
What is the best time to call Tehran from SGT?
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, SGT or Tehran?
SGT is 4 hours 30 minutes behind Tehran. When it is 12:00 PM in SGT it is 7:30 AM in Tehran.
Do SGT and Tehran use different time zones?
SGT uses SGT at UTC+08:00, while Tehran (Iran) uses IRST at UTC+03:30. The IANA identifiers are Asia/Singapore and Asia/Tehran.
Does daylight saving time affect the SGT–Tehran difference?
Neither zone observes daylight saving time, so the -4h 30m offset between SGT and Tehran is fixed all year.
Which other cities share SGT's time zone?
SGT also covers Singapore.
Which countries use SGT, SGT's zone?
SGT is used in Singapore.
Is there a day difference between SGT and Tehran?
Not normally. The -4h 30m gap only pushes the date over the previous day.
What is the time difference between SGT and Tehran?
Tehran is -4h 30m from SGT.
What timezone is SGT in?
SGT operates on its local timezone.
What timezone is Tehran in?
Tehran operates on Iran Standard Time (IRST), UTC+3:30. Iran's unique half-hour offset makes Tehran time distinctive for regional business coordination.
What are the business hours in Tehran?
Standard business hours in Tehran are 8:00 AM - 4:00 PM IRST.
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 SGT, what time is it in Tehran?
When it is 12:00 AM (midnight) in SGT (SGT), it is -4h 30m later in Tehran (IRST).
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