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 EST

-8h 30m

Tehran

IRSTSOURCE

Iran · UTC+03:30

HH12

MM00

12:00 (24-hr)

12 AM6 AM12 PM6 PM12 AM

EST

UTC-04:00☀ DST active

HH03

MM30

03:30 (24-hr)

12 AM6 AM12 PM6 PM12 AM

Quick Reference

Time Conversion Table

Tehran

EST

12:00 AM

4:30 PM-1

2:00 AM

6:30 PM-1

4:00 AM

8:30 PM-1

6:00 AM

10:30 PM-1

8:00 AM

12:30 AM

10:00 AM

2:30 AM

12:00 PM

4:30 AM

2:00 PM

6:30 AM

4:00 PM

8:30 AM

6:00 PM

10:30 AM

8:00 PM

12:30 PM

10:00 PM

2:30 PM

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

IRST and EST on the World Map

The map below highlights the IRST (Iran Standard Time) and EST (Eastern Standard Time) timezone regions across the globe.

IRST Zone

→

EST 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

EST – Eastern Standard Time

UTC-05:00

Eastern Standard Time (EST) is the time zone for the eastern United States and Canada, 5 hours behind UTC.

Countries in EST

United States (Eastern)Canada (Ontario, Quebec)Mexico (Quintana Roo)PanamaJamaicaCayman IslandsHaitiBahamasTurks and CaicosColombiaPeruEcuador

Major Cities in EST

New York CityWashington D.C.MiamiTorontoPhiladelphiaAtlantaBostonMontrealDetroitCharlotteIndianapolisOttawaTampaOrlandoClevelandPittsburgh

Key Facts about EST

•EST is the most widely used time zone in the United States by population.
•The New York Stock Exchange (NYSE) and NASDAQ operate on Eastern Time, opening at 9:30 AM EST.
•23 US states are fully or partially in the Eastern Time Zone.
•EST was established by the Standard Time Act of 1918.
•Over 47% of the US population lives in the Eastern Time Zone.

Daylight Saving:Yes – switches to EDT

Learn more about EST 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 vs EST: Offsets, DST and Best Call Times

Tehran runs on Iran Standard Time (IRST) at UTC+03:30. EST runs on Eastern Standard Time (EST) at UTC-05:00. That puts Tehran 8 hours 30 minutes behind EST — a difference of -8h 30m at the current offsets.

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

Tehran to EST time conversion table

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

Why people convert Tehran to EST time

Scheduling a call from Tehran to EST: a 10:00 AM start in Tehran lands at 1:30 AM in EST, so you can confirm the slot without doing the arithmetic yourself.
Handling a -8h 30m gap: Tehran and EST have no overlap inside a normal 9-to-5 day, so real-time meetings need an early-morning or late-evening slot on one side. 9:00 AM in EST is 12:30 AM in Tehran.
Watching a live event or market open: Tehran viewers need 12:30 AM in EST to catch a 9:00 AM start there, and 8:30 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 -8h 30m gap is not.
With a -8h 30m gap there is no shared 9-to-5 window, so alternate the early start: one week Tehran takes the early slot, the next week EST does.

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 EST (Eastern Standard Time)

Eastern Standard Time (EST) is observed during the winter months in the eastern part of North America. It covers 23 US states and parts of Canada including Ontario and Quebec. EST is the most populous time zone in the United States, home to major financial centers like New York City and global organizations headquartered in Washington D.C. During daylight saving time (March–November), clocks shift to Eastern Daylight Time (EDT, UTC-04:00). The time zone also covers parts of the Caribbean and Central America including Panama, Jamaica, and the Cayman Islands.

Best time to call between Tehran and EST

With a -8h 30m offset there is no overlap inside a normal 9 AM – 5 PM day. EST opens at 9:00 AM EST, which is 12:30 AM in Tehran, so real-time calls need an early-morning or late-evening slot on one side.

Business hours overlap

Tehran and EST have no shared working hours because of the -8h 30m gap. Teams need to alternate early starts or rely on asynchronous handovers.

Tehran is 8 hours 30 minutes behind EST (IRST UTC+03:30 → EST UTC-05:00). There is no shared 9-to-5 window, so plan around an early or late slot. Remember to re-check around daylight-saving transitions.

🕐 Daylight Saving Time Info

Tehran

Does not observe DST

EST

☀ Currently in DST

Standard: UTC-05:00 · DST: UTC-04:00

Clocks fall back on Sun, Nov 1, 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 EST?

Tehran (IRST, UTC+03:30) is 8 hours 30 minutes behind EST (EST, UTC-05:00). The gap is currently -8h 30m.

How do I convert Tehran time to EST time?

Add -8h 30m to Tehran local time. For example, 9:00 AM in Tehran is 12:30 AM in EST.

What time is it in EST right now?

EST uses EST at UTC-05:00. Use the live converter at the top of this page — it updates in real time and already accounts for the -8h 30m offset from Tehran.

What is the best time to call EST from Tehran?

There is no shared working-hours window because of the -8h 30m gap. The closest option is 1:00 PM in Tehran, which is 4:30 AM in EST.

Which is behind, Tehran or EST?

Tehran is 8 hours 30 minutes behind EST. When it is 12:00 PM in Tehran it is 3:30 AM in EST.

Do Tehran and EST use different time zones?

Tehran (Iran) uses IRST at UTC+03:30, while EST uses EST at UTC-05:00. The IANA identifiers are Asia/Tehran and America/New_York.

Does daylight saving time affect the Tehran–EST difference?

Neither zone observes daylight saving time, so the -8h 30m offset between Tehran and EST 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 EST?

Not normally. The -8h 30m gap only pushes the date over the previous day.

What is the time difference between Tehran and EST?

EST is -8h 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.

What timezone is EST in?

EST operates on its local timezone.

What are the business hours in Tehran?

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

Which countries use IRST (Iran Standard Time)?

IRST is used in Iran.

Does IRST observe daylight saving time?

Yes, IRST switches to IRDT during summer months.

What are some interesting 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).

Which cities are in the EST timezone?

Major cities in the EST timezone include New York City, Washington D.C., Miami, Toronto, Philadelphia, Atlanta, Boston, Montreal.

What is the UTC offset for EST?

Eastern Standard Time (EST) is at UTC-05:00. During daylight saving time, it shifts to EDT.

What should I know about the EST timezone?

EST is the most widely used time zone in the United States by population. The New York Stock Exchange (NYSE) and NASDAQ operate on Eastern Time, opening at 9:30 AM EST.