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).

PDT to IRST

+10h 30m

PDT

PDTSOURCE

UTC-07:00☀ DST active

HH12

MM00

12:00 (24-hr)

12 AM6 AM12 PM6 PM12 AM

IRST

UTC+03:30

HH10

MM30

22:30 (24-hr)

12 AM6 AM12 PM6 PM12 AM

Quick Reference

Time Conversion Table

PDT

IRST

12:00 AM

10:30 AM

2:00 AM

12:30 PM

4:00 AM

2:30 PM

6:00 AM

4:30 PM

8:00 AM

6:30 PM

10:00 AM

8:30 PM

12:00 PM

10:30 PM

2:00 PM

12:30 AM+1

4:00 PM

2:30 AM+1

6:00 PM

4:30 AM+1

8:00 PM

6:30 AM+1

10:00 PM

8:30 AM+1

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

PDT and IRST on the World Map

The map below highlights the PDT (Pacific Daylight Time) and IRST (Iran Standard Time) timezone regions across the globe.

PDT Zone

→

IRST Zone

Explore all world timezones interactively →

PDT – Pacific Daylight Time

UTC-07:00

Pacific Daylight Time (PDT) is the daylight saving offset on the US/Canada Pacific coast, 7 hours behind UTC.

Countries in PDT

United States (Pacific)Canada (British Columbia)Mexico (Baja California)

Major Cities in PDT

Los AngelesSan FranciscoSeattleVancouverPortland

Key Facts about PDT

•PDT aligns with MST at UTC-07:00.
•Tech company earnings calls often reference PDT/PST times.

Daylight Saving:Yes – switches to PST

Learn more about PDT 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

PDT vs IRST: Offsets, DST and Best Call Times

PDT runs on Pacific Daylight Time (PDT) at UTC-07:00. IRST runs on Iran Standard Time (IRST) at UTC+03:30. That puts PDT 10 hours 30 minutes ahead of IRST — a difference of +10h 30m at the current offsets.

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

PDT to IRST time conversion table

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

Why people convert PDT to IRST time

Scheduling a call from PDT to IRST: a 10:00 AM start in PDT lands at 8:30 PM in IRST, so you can confirm the slot without doing the arithmetic yourself.
Handling a +10h 30m gap: PDT and IRST 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 IRST is 7:30 PM in PDT.
Coordinating a PDT-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 PDT" is unambiguous; "3 PM" across a +10h 30m gap is not.
With a +10h 30m gap there is no shared 9-to-5 window, so alternate the early start: one week PDT takes the early slot, the next week IRST does.

About PDT (Pacific Daylight Time)

Pacific Daylight Time (PDT) is observed from March to November on the Pacific coast. During PDT, the west coast is 7 hours behind UTC and only 2 hours behind the east coast's EDT.

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 PDT and IRST

With a +10h 30m offset there is no overlap inside a normal 9 AM – 5 PM day. IRST opens at 9:00 AM IRST, which is 7:30 PM in PDT, so real-time calls need an early-morning or late-evening slot on one side.

Business hours overlap

PDT and IRST have no shared working hours because of the +10h 30m gap. Teams need to alternate early starts or rely on asynchronous handovers.

PDT is 10 hours 30 minutes ahead of IRST (PDT UTC-07:00 → IRST UTC+03:30). 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

PDT

☀ Currently in DST

Standard: UTC-08:00 · DST: UTC-07:00

Clocks fall back on Sun, Nov 1, 2026

IRST

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 PDT and IRST?

PDT (PDT, UTC-07:00) is 10 hours 30 minutes ahead of IRST (IRST, UTC+03:30). The gap is currently +10h 30m.

How do I convert PDT time to IRST time?

Add +10h 30m to PDT local time. For example, 9:00 AM in PDT is 7:30 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 +10h 30m offset from PDT.