Does it handle Daylight Saving Time?

Yes, the tool automatically adjusts for Daylight Saving Time based on the specific date you select, ensuring accurate conversions year-round.

Can I add multiple cities?

Yes, you can add as many cities as you need to the dashboard to compare times across your entire global network simultaneously.

Oslo to Tehran

+1h 30m

Oslo

CESTSOURCE

Norway · UTC+02:00☀ DST active

HH12

MM00

12:00 (24-hr)

12 AM6 AM12 PM6 PM12 AM

Tehran

IRST

Iran · UTC+03:30

HH01

MM30

13:30 (24-hr)

12 AM6 AM12 PM6 PM12 AM

Quick Reference

Time Conversion Table

Oslo

Tehran

12:00 AM

1:30 AM

2:00 AM

3:30 AM

4:00 AM

5:30 AM

6:00 AM

7:30 AM

8:00 AM

9:30 AM

10:00 AM

11:30 AM

12:00 PM

1:30 PM

2:00 PM

3:30 PM

4:00 PM

5:30 PM

6:00 PM

7:30 PM

8:00 PM

9:30 PM

10:00 PM

11:30 PM

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

CEST and IRST on the World Map

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

CEST Zone

→

IRST Zone

Explore all world timezones interactively →

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

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

About Oslo

Wikipedia

Oslo operates on Central European Time (CET/CEST). As home to the world's largest sovereign wealth fund and major oil firms, Oslo influences global energy markets.

Population:693,000

Metro:1.5 million

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

Currency:NOK (kr)

Stock Exchange:OSE (Oslo Stock Exchange)

Key Landmarks

Oslo Opera HouseVigeland ParkAkershus FortressMunch MuseumRoyal Palace

Did You Know?

Oslo aims to be car-free by 2030.

Learn more about CEST timezone →

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 →

Comparing Time Zones: Oslo and Tehran

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

In practice, when it is 9:00 AM in Oslo it is 10:30 AM in Tehran. Midnight in Oslo is 1:30 AM in Tehran.Oslo observes daylight saving time while Tehran does not, so the gap narrows or widens by an hour part of the year.

Oslo to Tehran time conversion table

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

Why people convert Oslo to Tehran time

Scheduling a call from Oslo to Tehran: a 10:00 AM start in Oslo lands at 11:30 AM in Tehran, so you can confirm the slot without doing the arithmetic yourself.
Finding shared working hours: both Oslo and Tehran are inside the 9-to-5 working day between 9:00 AM and 3:30 PM CEST time (10:30 AM–5:00 PM IRST). That is roughly 6 hours 30 minutes of usable overlap.
Booking travel or deliveries: tracking Tehran local time against Oslo keeps pickup windows and arrival estimates honest across the +1h 30m offset.

Always state the zone abbreviation, not just the hour. "3:00 PM CEST" is unambiguous; "3 PM" across a +1h 30m gap is not.
Block 9:00 AM–3:30 PM CEST as the recurring meeting window if you work primarily from Oslo and need Tehran colleagues present.
Oslo: Clocks fall back on Sun, Oct 25, 2026. Re-check this page after that date because the offset changes and so does the +1h 30m gap.

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.

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 Oslo and Tehran

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

Business hours overlap

Oslo and Tehran share 6 hours of working-hours overlap (9:00 AM–3:30 PM CEST), so scheduling a live meeting is straightforward.

Oslo is 1 hour 30 minutes ahead of Tehran (CEST UTC+02:00 → IRST UTC+03:30). The shared working window is 9:00 AM–3:30 PM CEST. Remember to re-check around daylight-saving transitions.

🕐 Daylight Saving Time Info

Oslo

☀ Currently in DST

Standard: UTC+01:00 · DST: UTC+02:00

Clocks fall back on Sun, Oct 25, 2026

Tehran

Does not observe DST

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 Oslo and Tehran?

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

How do I convert Oslo time to Tehran time?

Add +1h 30m to Oslo local time. For example, 9:00 AM in Oslo is 10:30 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 +1h 30m offset from Oslo.

What is the best time to call Tehran from Oslo?

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

Which is ahead, Oslo or Tehran?

Oslo is 1 hour 30 minutes ahead of Tehran. When it is 12:00 PM in Oslo it is 1:30 PM in Tehran.

Do Oslo and Tehran use different time zones?

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

Does daylight saving time affect the Oslo–Tehran difference?

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

Which other cities share Oslo's time zone?

CEST also covers Paris, Berlin, Rome, Madrid, Amsterdam, Brussels, Vienna, Warsaw and 10 more.

Which countries use CEST, Oslo's zone?

CEST is used in Germany, France, Italy, Spain, Netherlands, Belgium, Austria, Switzerland and 19 more.

Is there a day difference between Oslo and Tehran?

Not normally. The +1h 30m gap only pushes the date over for late-evening times.

What is the time difference between Oslo and Tehran?

Tehran is +1h 30m from Oslo.

What timezone is Oslo in?

Oslo operates on Central European Time (CET/CEST). As home to the world's largest sovereign wealth fund and major oil firms, Oslo influences global energy markets.

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 Oslo?

Standard business hours in Oslo are 8:00 AM - 4:00 PM CET.

What are the business hours in Tehran?

Standard business hours in Tehran are 8:00 AM - 4:00 PM IRST.

What is the best time to schedule a call between Oslo and Tehran?

The best overlap for a call is when both cities are in business hours. Oslo works 8:00 AM - 4:00 PM CET and Tehran works 8:00 AM - 4:00 PM IRST (+1h 30m difference). Try scheduling during the overlapping window for maximum convenience.

What currencies are used in Oslo and Tehran?

Oslo uses NOK (kr) while Tehran uses IRR (﷼). Check current exchange rates when planning travel or business between these cities.

How do Oslo and Tehran compare in size?

Oslo has a population of approximately 693,000 (metro: 1.5 million), while Tehran has approximately 9.4 million (metro: 16.8 million).

What are the major landmarks in Oslo and Tehran?

Oslo is known for Oslo Opera House, Vigeland Park, Akershus Fortress. Tehran is famous for Azadi Tower, Golestan Palace, Grand Bazaar.

Do Oslo and Tehran have stock exchanges?

Yes. Oslo has the OSE (Oslo Stock Exchange) and Tehran has the TSE (Tehran Stock Exchange). The +1h 30m time difference affects trading hour overlaps between these exchanges.