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).

Tehran to CEST

-1h 30m

Tehran

IRSTSOURCE

Iran · UTC+03:30

HH12

MM00

12:00 (24-hr)

12 AM6 AM12 PM6 PM12 AM

CEST

UTC+02:00☀ DST active

HH10

MM30

10:30 (24-hr)

12 AM6 AM12 PM6 PM12 AM

Quick Reference

Time Conversion Table

Tehran

CEST

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 Summer 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

CEST – Central European Summer Time

UTC+02:00

Central European Summer Time (CEST) is the daylight saving time in Central Europe, 2 hours ahead of UTC.

Countries in CEST

GermanyFranceItalySpainNetherlandsBelgiumAustriaSwitzerlandPolandSwedenNorway

Major Cities in CEST

ParisBerlinRomeMadridAmsterdamViennaStockholm

Key Facts about CEST

•CEST runs from the last Sunday of March to the last Sunday of October.
•The EU has voted to abolish clock changes but implementation has been delayed.
•CEST shares the same offset as EET (UTC+02:00).

Daylight Saving:Yes – switches to CET

Learn more about CEST on Wikipedia

About Tehran

Wikipedia

Tehran operates on Iran Standard Time (IRST), UTC+3:30. Iran's unique half-hour offset makes Tehran time distinctive for regional business coordination.

Population:9.4 million

Metro:16.8 million

Business Hours:8:00 AM - 4:00 PM IRST

Currency:IRR (﷼)

Stock Exchange:TSE (Tehran Stock Exchange)

Key Landmarks

Azadi TowerGolestan PalaceGrand BazaarMilad TowerTabiat Bridge

Did You Know?

Iran Standard Time (IRST) is one of few timezones with a 30-minute offset (UTC+3:30).

Learn more about IRST timezone →

Tehran to CEST Time Difference – Complete Guide

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

In practice, when it is 9:00 AM in Tehran it is 7:30 AM in CEST. Midnight in Tehran is 10:30 PM in CEST. Neither zone observes daylight saving time, so the offset between them stays constant all year.

Tehran to CEST time conversion table

Tehran (IRST)	CEST (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 Tehran to CEST time

Scheduling a call from Tehran to CEST: a 10:00 AM start in Tehran lands at 8:30 AM in CEST, so you can confirm the slot without doing the arithmetic yourself.
Finding shared working hours: both Tehran and CEST 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: Tehran viewers need 7:30 AM in CEST to catch a 9:00 AM start there, and 1:30 AM if the event is anchored to Tehran.

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 Tehran and need CEST colleagues present.

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 CEST (Central European Summer Time)

Central European Summer Time (CEST) is observed from the last Sunday of March to the last Sunday of October across most of Europe. During CEST, clocks are 2 hours ahead of UTC. The EU has debated abolishing seasonal clock changes since 2019.

Best time to call between Tehran and CEST

Both Tehran and CEST 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

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

Tehran is 1 hour 30 minutes behind CEST (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

Tehran

Does not observe DST

CEST

☀ 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 Tehran and CEST?

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

How do I convert Tehran time to CEST time?

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

What time is it in CEST right now?

CEST 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 Tehran.

What is the best time to call CEST from Tehran?

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, Tehran or CEST?

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

Do Tehran and CEST use different time zones?

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

Does daylight saving time affect the Tehran–CEST difference?

Neither zone observes daylight saving time, so the -1h 30m offset between Tehran and CEST is fixed all year.

Which other cities share Tehran's time zone?

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

Which countries use IRST, Tehran's zone?

IRST is used in Iran.

Is there a day difference between Tehran and CEST?

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

What is the time difference between Tehran and CEST?

CEST is -1h 30m from Tehran.

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.