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.

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).

UTC to IRST

Q: What is UTC?

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

+3h 30m

UTC

UTCSOURCE

UTC+00:00

HH12

MM00

12:00 (24-hr)

12 AM6 AM12 PM6 PM12 AM

IRST

UTC+03:30

HH03

MM30

15:30 (24-hr)

12 AM6 AM12 PM6 PM12 AM

Quick Reference

Time Conversion Table

UTC

IRST

12:00 AM

3:30 AM

2:00 AM

5:30 AM

4:00 AM

7:30 AM

6:00 AM

9:30 AM

8:00 AM

11:30 AM

10:00 AM

1:30 PM

12:00 PM

3:30 PM

2:00 PM

5:30 PM

4:00 PM

7:30 PM

6:00 PM

9:30 PM

8:00 PM

11:30 PM

10:00 PM

1:30 AM+1

Green rows indicate typical business hours (9 AM - 5 PM)

UTC and IRST on the World Map

The map below highlights the UTC (Coordinated Universal Time) and IRST (Iran Standard Time) timezone regions across the globe.

UTC Zone

→

IRST Zone

Explore all world timezones interactively →

UTC – Coordinated Universal Time

UTC+00:00

Coordinated Universal Time (UTC) is the world's primary time standard, used as the basis for civil time worldwide.

Countries in UTC

Used worldwide as referenceSame zone as: UK, Ireland, Iceland, Portugal, Ghana

Major Cities in UTC

LondonDublinReykjavikAccraLisbonDakar

Key Facts about UTC

•UTC is the basis for all civil time zones worldwide.
•The abbreviation 'UTC' is a compromise between English (CUT) and French (TUC).
•UTC is based on atomic clocks and is accurate to within a nanosecond per day.
•Servers and databases worldwide store timestamps in UTC to avoid timezone confusion.
•Leap seconds are occasionally added to UTC to keep it aligned with Earth's rotation.

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

Learn more about UTC 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

UTC vs IRST: Offsets, DST and Best Call Times

UTC runs on Coordinated Universal Time (UTC) at UTC+00:00. IRST runs on Iran Standard Time (IRST) at UTC+03:30. That puts UTC 3 hours 30 minutes ahead of IRST — a difference of +3h 30m at the current offsets.

In practice, when it is 9:00 AM in UTC it is 12:30 PM in IRST. Midnight in UTC is 3:30 AM in IRST. Neither zone observes daylight saving time, so the offset between them stays constant all year.

UTC to IRST time conversion table

UTC (UTC)	IRST (IRST)	Day
12:00 AM	3:30 AM	same day
6:00 AM	9:30 AM	same day
7:00 AM	10:30 AM	same day
8:00 AM	11:30 AM	same day
9:00 AM	12:30 PM	same day
12:00 PM	3:30 PM	same day
3:00 PM	6:30 PM	same day
5:00 PM	8:30 PM	same day
6:00 PM	9:30 PM	same day
9:00 PM	12:30 AM	next day

Why people convert UTC to IRST time

Scheduling a call from UTC to IRST: a 10:00 AM start in UTC lands at 1:30 PM in IRST, so you can confirm the slot without doing the arithmetic yourself.
Finding shared working hours: both UTC and IRST are inside the 9-to-5 working day between 9:00 AM and 1:30 PM UTC time (12:30 PM–5:00 PM IRST). That is roughly 4 hours 30 minutes of usable overlap.
Coordinating a UTC-based team with IRST contacts: quoting times in the other side's local clock — not your own — removes the single biggest source of missed meetings.

Always state the zone abbreviation, not just the hour. "3:00 PM UTC" is unambiguous; "3 PM" across a +3h 30m gap is not.
Block 9:00 AM–1:30 PM UTC as the recurring meeting window if you work primarily from UTC and need IRST colleagues present.

About UTC (Coordinated Universal Time)

Coordinated Universal Time (UTC) is the primary time standard by which the world regulates clocks and time. It is effectively the successor to GMT and is based on International Atomic Time with leap seconds added to keep it synchronized with Earth's rotation. UTC is used in aviation, computing, navigation, weather forecasting, and the International Space Station. Most programming languages and databases store timestamps in UTC.

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 UTC and IRST

Both UTC and IRST sit inside the 9 AM – 5 PM working day between 9:00 AM–1:30 PM UTC, which is 12:30 PM–5:00 PM IRST. That gives roughly 4 hours and 30 minutes of shared time — the safest window for a live call or meeting.

Business hours overlap

UTC and IRST overlap for about 4 hours during the working day — enough for meetings if you avoid the edges of the window.

UTC is 3 hours 30 minutes ahead of IRST (UTC UTC+00:00 → IRST UTC+03:30). The shared working window is 9:00 AM–1:30 PM UTC. 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 UTC and IRST?

UTC (UTC, UTC+00:00) is 3 hours 30 minutes ahead of IRST (IRST, UTC+03:30). The gap is currently +3h 30m.

How do I convert UTC time to IRST time?

Add +3h 30m to UTC local time. For example, 9:00 AM in UTC is 12:30 PM 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 +3h 30m offset from UTC.