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 CLT

-7h 30m

IRST

IRSTSOURCE

UTC+03:30

HH12

MM00

12:00 (24-hr)

12 AM6 AM12 PM6 PM12 AM

CLT

UTC-03:00☀ DST active

HH04

MM30

04:30 (24-hr)

12 AM6 AM12 PM6 PM12 AM

Quick Reference

Time Conversion Table

IRST

CLT

12:00 AM

5:30 PM-1

2:00 AM

7:30 PM-1

4:00 AM

9:30 PM-1

6:00 AM

11:30 PM-1

8:00 AM

1:30 AM

10:00 AM

3:30 AM

12:00 PM

5:30 AM

2:00 PM

7:30 AM

4:00 PM

9:30 AM

6:00 PM

11:30 AM

8:00 PM

1:30 PM

10:00 PM

3:30 PM

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

IRST and CLT on the World Map

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

IRST Zone

→

CLT 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

CLT – Chile Standard Time

UTC-04:00

Chile Standard Time (CLT) is the time zone for continental Chile, 4 hours behind UTC.

Countries in CLT

Chile

Major Cities in CLT

SantiagoValparaísoConcepciónViña del MarAntofagasta

Key Facts about CLT

•Chile observes daylight saving time, switching to CLST (UTC-03:00) in summer.
•Santiago is the largest city in Chile with over 6 million in the metro area.
•Chile spans over 4,300 km from north to south but uses one timezone.

Daylight Saving:Yes – switches to CLST

Learn more about CLT on Wikipedia

IRST to CLT Time Difference – Complete Guide

IRST runs on Iran Standard Time (IRST) at UTC+03:30. CLT runs on Chile Standard Time (CLT) at UTC-04:00. That puts IRST 7 hours 30 minutes behind CLT — a difference of -7h 30m at the current offsets.

In practice, when it is 9:00 AM in IRST it is 1:30 AM in CLT. Midnight in IRST is 4:30 PM in CLT. Neither zone observes daylight saving time, so the offset between them stays constant all year.

IRST to CLT time conversion table

IRST (IRST)	CLT (CLT)	Day
12:00 AM	4:30 PM	previous day
6:00 AM	10:30 PM	previous day
7:00 AM	11:30 PM	previous day
8:00 AM	12:30 AM	same day
9:00 AM	1:30 AM	same day
12:00 PM	4:30 AM	same day
3:00 PM	7:30 AM	same day
5:00 PM	9:30 AM	same day
6:00 PM	10:30 AM	same day
9:00 PM	1:30 PM	same day

Why people convert IRST to CLT time

Scheduling a call from IRST to CLT: a 10:00 AM start in IRST lands at 2:30 AM in CLT, so you can confirm the slot without doing the arithmetic yourself.
Finding shared working hours: both IRST and CLT are inside the 9-to-5 working day between 4:30 PM and 5:00 PM IRST time (9:00 AM–9:30 AM CLT). That is roughly 0 hours 30 minutes of usable overlap.
Watching a live event or market open: IRST viewers need 1:30 AM in CLT to catch a 9:00 AM start there, and 7:30 AM if the event is anchored to IRST.

Always state the zone abbreviation, not just the hour. "3:00 PM IRST" is unambiguous; "3 PM" across a -7h 30m gap is not.
Block 4:30 PM–5:00 PM IRST as the recurring meeting window if you work primarily from IRST and need CLT 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 CLT (Chile Standard Time)

Chile Standard Time (CLT) is the standard time in Chile. During summer months (October to March), Chile switches to Chile Summer Time (CLST, UTC-03:00). Chile is the longest north-south country in the world.

Best time to call between IRST and CLT

Both IRST and CLT sit inside the 9 AM – 5 PM working day between 4:30 PM–5:00 PM IRST, which is 9:00 AM–9:30 AM CLT. That gives roughly 0 hours and 30 minutes of shared time — the safest window for a live call or meeting.

Business hours overlap

IRST and CLT overlap for only 30 minutes (4:30 PM–5:00 PM IRST), so meetings have to be booked precisely.

IRST is 7 hours 30 minutes behind CLT (IRST UTC+03:30 → CLT UTC-04:00). The shared working window is 4:30 PM–5:00 PM IRST. Remember to re-check around daylight-saving transitions.

🕐 Daylight Saving Time Info

IRST

Does not observe DST

CLT

☀ Currently in DST

Standard: UTC-04:00 · DST: UTC-03:00

Clocks fall back on Sun, Apr 4, 2027

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 CLT?

IRST (IRST, UTC+03:30) is 7 hours 30 minutes behind CLT (CLT, UTC-04:00). The gap is currently -7h 30m.

How do I convert IRST time to CLT time?

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

What time is it in CLT right now?

CLT uses CLT at UTC-04:00. Use the live converter at the top of this page — it updates in real time and already accounts for the -7h 30m offset from IRST.

What is the best time to call CLT from IRST?

Call between 4:30 PM and 5:00 PM IRST — that maps to 9:00 AM–9:30 AM CLT and keeps both parties inside the working day.

Which is behind, IRST or CLT?

IRST is 7 hours 30 minutes behind CLT. When it is 12:00 PM in IRST it is 4:30 AM in CLT.

Does daylight saving time affect the IRST–CLT difference?

Neither zone observes daylight saving time, so the -7h 30m offset between IRST and CLT is fixed all year.

Which other cities share IRST's time zone?

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

Which countries use IRST, IRST's zone?

IRST is used in Iran.

Is there a day difference between IRST and CLT?

Not normally. The -7h 30m gap only pushes the date over the previous day.

What is the time difference between IRST and CLT?

CLT is -7h 30m from IRST.

What timezone is IRST in?

IRST operates on its local timezone.

What timezone is CLT in?

CLT operates on its local timezone.

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 CLT timezone?

Major cities in the CLT timezone include Santiago, Valparaíso, Concepción, Viña del Mar, Antofagasta.

What is the UTC offset for CLT?

Chile Standard Time (CLT) is at UTC-04:00. During daylight saving time, it shifts to CLST.

What should I know about the CLT timezone?

Chile observes daylight saving time, switching to CLST (UTC-03:00) in summer. Santiago is the largest city in Chile with over 6 million in the metro area.