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 PDT

-10h 30m

IRST

IRSTSOURCE

UTC+03:30

HH12

MM00

12:00 (24-hr)

12 AM6 AM12 PM6 PM12 AM

PDT

UTC-07:00☀ DST active

HH01

MM30

01:30 (24-hr)

12 AM6 AM12 PM6 PM12 AM

Quick Reference

Time Conversion Table

IRST

PDT

12:00 AM

1:30 PM-1

2:00 AM

3:30 PM-1

4:00 AM

5:30 PM-1

6:00 AM

7:30 PM-1

8:00 AM

9:30 PM-1

10:00 AM

11:30 PM-1

12:00 PM

1:30 AM

2:00 PM

3:30 AM

4:00 PM

5:30 AM

6:00 PM

7:30 AM

8:00 PM

9:30 AM

10:00 PM

11:30 AM

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

IRST and PDT on the World Map

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

IRST Zone

→

PDT 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

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 vs PDT: Offsets, DST and Best Call Times

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

In practice, when it is 9:00 AM in IRST it is 10:30 PM in PDT on the previous day. Midnight in IRST is 1:30 PM in PDT. Neither zone observes daylight saving time, so the offset between them stays constant all year.

IRST to PDT time conversion table

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

Why people convert IRST to PDT time

Scheduling a call from IRST to PDT: a 10:00 AM start in IRST lands at 11:30 PM in PDT the previous day, so you can confirm the slot without doing the arithmetic yourself.
Handling a -10h 30m gap: IRST and PDT 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 PDT is 10:30 PM in IRST.
Keeping family and friends in sync: knowing that 8:00 PM in IRST is 9:30 AM in PDT makes it easy to avoid calling at 3 AM.

Always state the zone abbreviation, not just the hour. "3:00 PM IRST" 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 IRST takes the early slot, the next week PDT 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 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.

Best time to call between IRST and PDT

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

Business hours overlap

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

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

IRST

Does not observe DST

PDT

☀ Currently in DST

Standard: UTC-08:00 · DST: UTC-07:00

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 IRST and PDT?

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

How do I convert IRST time to PDT time?

Add -10h 30m to IRST local time. For example, 9:00 AM in IRST is 10:30 PM in PDT (previous day).

What time is it in PDT right now?

PDT uses PDT at UTC-07:00. Use the live converter at the top of this page — it updates in real time and already accounts for the -10h 30m offset from IRST.