Does it account for Daylight Saving Time?

Yes, our converter uses the IANA timezone database, which includes all current DST rules for every timezone in the world.

UTC (Coordinated Universal Time) is the primary time standard by which the world regulates clocks. All timezones are defined as offsets from UTC.

Can I compare multiple timezones at once?

Yes, you can add multiple cities or timezones and see the equivalent times side by side.

How many timezones are there in the world?

There are 38 distinct UTC offsets in use, ranging from UTC-12 to UTC+14. This includes half-hour (UTC+5:30 India, UTC+9:30 Australia) and 45-minute offsets (UTC+5:45 Nepal, UTC+8:45 Australia).

What is the International Date Line?

The International Date Line (IDL) runs roughly along the 180° meridian in the Pacific Ocean. When you cross it westward, you gain a day; crossing eastward, you lose a day.

Why do some timezones have 30 or 45 minute offsets?

Countries chose offsets that best matched their solar noon. India uses UTC+5:30 and Nepal uses UTC+5:45 because standard hourly offsets didn't align well with their geography.

Which country has the most timezones?

France has the most (12 timezones) due to overseas territories. Russia spans 11 timezones. The US has 6 (including Hawaii and Alaska).

SGT to IRST

-4h 30m

SGT

SGTSOURCE

UTC+08:00

HH12

MM00

12:00 (24-hr)

12 AM6 AM12 PM6 PM12 AM

IRST

UTC+03:30

HH07

MM30

07:30 (24-hr)

12 AM6 AM12 PM6 PM12 AM

Quick Reference

Time Conversion Table

SGT

IRST

12:00 AM

7:30 PM-1

2:00 AM

9:30 PM-1

4:00 AM

11:30 PM-1

6:00 AM

1:30 AM

8:00 AM

3:30 AM

10:00 AM

5:30 AM

12:00 PM

7:30 AM

2:00 PM

9:30 AM

4:00 PM

11:30 AM

6:00 PM

1:30 PM

8:00 PM

3:30 PM

10:00 PM

5:30 PM

Green 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 Zone

→

IRST Zone

Explore all world timezones interactively →

SGT – Singapore Standard Time

UTC+08:00

Singapore Standard Time (SGT) is the time zone for Singapore, 8 hours ahead of UTC.

Countries in SGT

Singapore

Major Cities in SGT

Singapore

Key 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.
•The Singapore Exchange (SGX) operates on SGT.

Daylight Saving:No – UTC+08:00 year-round

Learn more about SGT on Wikipedia

IRST – Iran Standard Time

UTC+03:30

Iran Standard Time (IRST) is the time zone for Iran, 3 hours and 30 minutes ahead of UTC.

Countries in IRST

Iran

Major Cities in IRST

TehranIsfahanMashhadTabrizShirazKaraj

Key Facts about IRST

•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.

Daylight Saving:Yes – switches to IRDT

Learn more about IRST on Wikipedia

Time Conversion Guide: SGT to IRST

SGT runs on Singapore Standard Time (SGT) at UTC+08:00. IRST runs on Iran Standard Time (IRST) at UTC+03:30. That puts SGT 4 hours 30 minutes behind IRST — 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 IRST. Midnight in SGT is 7:30 PM in IRST. Neither zone observes daylight saving time, so the offset between them stays constant all year.

SGT to IRST time conversion table

SGT (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 SGT to IRST time

Scheduling a call from SGT to IRST: a 10:00 AM start in SGT lands at 5:30 AM in IRST, so you can confirm the slot without doing the arithmetic yourself.
Finding shared working hours: both SGT 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 SGT 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 SGT 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 SGT and IRST

Both SGT 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

SGT and IRST 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 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:

⏳

History of Timekeeping

From sundials to atomic clocks - 5000 years of measuring time

🌍

How Time Zones Work

UTC, offsets, and why zones don't follow straight lines

☀️

Daylight Saving Time

DST dates, which countries observe it, and the ongoing debate

Frequently Asked Questions

What is the time difference between SGT and IRST?

SGT (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 SGT time to IRST time?

Add -4h 30m to SGT local time. For example, 9:00 AM in SGT 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 SGT.