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).

IRST to Brussels

-1h 30m

IRST

IRSTSOURCE

UTC+03:30

HH12

MM00

12:00 (24-hr)

12 AM6 AM12 PM6 PM12 AM

Brussels

CEST

Belgium · UTC+02:00☀ DST active

HH10

MM30

10:30 (24-hr)

12 AM6 AM12 PM6 PM12 AM

Quick Reference

Time Conversion Table

IRST

Brussels

12:00 AM

10:30 PM-1

2:00 AM

12:30 AM

4:00 AM

2:30 AM

6:00 AM

4:30 AM

8:00 AM

6:30 AM

10:00 AM

8:30 AM

12:00 PM

10:30 AM

2:00 PM

12:30 PM

4:00 PM

2:30 PM

6:00 PM

4:30 PM

8:00 PM

6:30 PM

10:00 PM

8:30 PM

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

IRST and CEST on the World Map

The map below highlights the IRST (Iran Standard Time) and CEST (Central European Time) timezone regions across the globe.

IRST Zone

→

CEST Zone

Explore all world timezones interactively →

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

CET – Central European Time

UTC+01:00

Central European Time (CET) is used across most of Western and Central Europe, 1 hour ahead of UTC.

Countries in CET

GermanyFranceItalySpainNetherlandsBelgiumAustriaSwitzerlandPolandCzech RepublicSwedenNorwayDenmarkHungaryCroatiaSerbiaSlovakiaSloveniaBosnia and HerzegovinaNorth MacedoniaAlbaniaMontenegroLuxembourgMaltaTunisiaAlgeriaNigeria

Major Cities in CET

ParisBerlinRomeMadridAmsterdamBrusselsViennaWarsawZurichStockholmOsloCopenhagenPragueBudapestBarcelonaMunichMilanLagos

Key Facts about CET

•CET covers more European countries than any other time zone.
•Spain uses CET despite being geographically aligned with GMT/WET.
•The Frankfurt Stock Exchange, Euronext (Amsterdam/Paris), and Borsa Italiana operate on CET.
•Over 500 million people live in the CET time zone.
•France moved to CET during the German occupation in WWII and never switched back.

Daylight Saving:Yes – switches to CEST

Learn more about CET on Wikipedia

About Brussels

Wikipedia

Brussels operates on Central European Time (CET/CEST). As the de facto EU capital and NATO headquarters, Brussels time drives European policy and business.

Population:1.2 million

Metro:2.1 million

Business Hours:9:00 AM - 5:00 PM CET

Currency:EUR (€)

Stock Exchange:Euronext Brussels

Key Landmarks

Grand PlaceAtomiumManneken PisEuropean ParliamentRoyal Palace

Did You Know?

Brussels is the de facto capital of the European Union.

Learn more about CEST timezone →

IRST to Brussels Time Difference – Complete Guide

IRST runs on Iran Standard Time (IRST) at UTC+03:30. Brussels runs on Central European Summer Time (CEST) at UTC+02:00, also currently on daylight saving time. That puts IRST 1 hour 30 minutes behind Brussels — a difference of -1h 30m at the current offsets.

In practice, when it is 9:00 AM in IRST it is 7:30 AM in Brussels. Midnight in IRST is 10:30 PM in Brussels.Brussels observes daylight saving time while IRST does not, so the gap narrows or widens by an hour part of the year.

IRST to Brussels time conversion table

IRST (IRST)	Brussels (CEST)	Day
12:00 AM	10:30 PM	previous day
6:00 AM	4:30 AM	same day
7:00 AM	5:30 AM	same day
8:00 AM	6:30 AM	same day
9:00 AM	7:30 AM	same day
12:00 PM	10:30 AM	same day
3:00 PM	1:30 PM	same day
5:00 PM	3:30 PM	same day
6:00 PM	4:30 PM	same day
9:00 PM	7:30 PM	same day

Why people convert IRST to Brussels time

Scheduling a call from IRST to Brussels: a 10:00 AM start in IRST lands at 8:30 AM in Brussels, so you can confirm the slot without doing the arithmetic yourself.
Finding shared working hours: both IRST and Brussels are inside the 9-to-5 working day between 10:30 AM and 5:00 PM IRST time (9:00 AM–3:30 PM CEST). That is roughly 6 hours 30 minutes of usable overlap.
Watching a live event or market open: IRST viewers need 7:30 AM in Brussels to catch a 9:00 AM start there, and 1:30 AM if the event is anchored to IRST.

Always state the zone abbreviation, not just the hour. "3:00 PM IRST" is unambiguous; "3 PM" across a -1h 30m gap is not.
Block 10:30 AM–5:00 PM IRST as the recurring meeting window if you work primarily from IRST and need Brussels colleagues present.
Brussels: Clocks fall back on Sun, Oct 25, 2026. Any meeting series spanning that date will shift by an hour in local time.

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.

About CET (Central European Time)

Central European Time (CET) is the standard time zone for most of Europe, covering over 30 countries from Spain to Poland, and from Norway to Italy. CET is 1 hour ahead of GMT and is used by the European Union's most populous nations. During summer, most CET countries switch to Central European Summer Time (CEST, UTC+02:00). Major European financial markets in Frankfurt, Paris, and Amsterdam operate on CET.

Best time to call between IRST and Brussels

Both IRST and Brussels sit inside the 9 AM – 5 PM working day between 10:30 AM–5:00 PM IRST, which is 9:00 AM–3:30 PM CEST. That gives roughly 6 hours and 30 minutes of shared time — the safest window for a live call or meeting.

Business hours overlap

IRST and Brussels share 6 hours of working-hours overlap (10:30 AM–5:00 PM IRST), so scheduling a live meeting is straightforward.

IRST is 1 hour 30 minutes behind Brussels (IRST UTC+03:30 → CEST UTC+02:00). The shared working window is 10:30 AM–5:00 PM IRST. Remember to re-check around daylight-saving transitions.

🕐 Daylight Saving Time Info

IRST

Does not observe DST

Brussels

☀ Currently in DST

Standard: UTC+01:00 · DST: UTC+02:00

Clocks fall back on Sun, Oct 25, 2026

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 IRST and Brussels?

IRST (IRST, UTC+03:30) is 1 hour 30 minutes behind Brussels (CEST, UTC+02:00). The gap is currently -1h 30m.

How do I convert IRST time to Brussels time?

Add -1h 30m to IRST local time. For example, 9:00 AM in IRST is 7:30 AM in Brussels.

What time is it in Brussels right now?

Brussels uses CEST at UTC+02:00. Use the live converter at the top of this page — it updates in real time and already accounts for the -1h 30m offset from IRST.

What is the best time to call Brussels from IRST?

Call between 10:30 AM and 5:00 PM IRST — that maps to 9:00 AM–3:30 PM CEST and keeps both parties inside the working day.

Which is behind, IRST or Brussels?

IRST is 1 hour 30 minutes behind Brussels. When it is 12:00 PM in IRST it is 10:30 AM in Brussels.

Do IRST and Brussels use different time zones?

IRST uses IRST at UTC+03:30, while Brussels (Belgium) uses CEST at UTC+02:00. The IANA identifiers are Asia/Tehran and Europe/Brussels.

Does daylight saving time affect the IRST–Brussels difference?

Yes at the moment: Brussels is on daylight saving time and IRST is not, so the -1h 30m gap shifts by an hour when exactly one of them changes clocks.

Which other cities share IRST's time zone?

IRST also covers Tehran, Isfahan, Mashhad, Tabriz, Shiraz, Karaj.

Which countries use IRST, IRST's zone?

IRST is used in Iran.

Is there a day difference between IRST and Brussels?

Not normally. The -1h 30m gap only pushes the date over the previous day.

What is the time difference between IRST and Brussels?

Brussels is -1h 30m from IRST.

What timezone is IRST in?

IRST operates on its local timezone.

What timezone is Brussels in?

Brussels operates on Central European Time (CET/CEST). As the de facto EU capital and NATO headquarters, Brussels time drives European policy and business.