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 NZDT

+9h 30m

IRST

IRSTSOURCE

UTC+03:30

HH12

MM00

12:00 (24-hr)

12 AM6 AM12 PM6 PM12 AM

NZDT

UTC+13:00☀ DST active

HH09

MM30

21:30 (24-hr)

12 AM6 AM12 PM6 PM12 AM

Quick Reference

Time Conversion Table

IRST

NZDT

12:00 AM

9:30 AM

2:00 AM

11:30 AM

4:00 AM

1:30 PM

6:00 AM

3:30 PM

8:00 AM

5:30 PM

10:00 AM

7:30 PM

12:00 PM

9:30 PM

2:00 PM

11:30 PM

4:00 PM

1:30 AM+1

6:00 PM

3:30 AM+1

8:00 PM

5:30 AM+1

10:00 PM

7:30 AM+1

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

IRST and NZDT on the World Map

The map below highlights the IRST (Iran Standard Time) and NZDT (New Zealand Daylight Time) timezone regions across the globe.

IRST Zone

→

NZDT 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

NZDT – New Zealand Daylight Time

UTC+13:00

New Zealand Daylight Time (NZDT, UTC+13:00) is New Zealand's summer time zone, one of the earliest offsets in the world.

Countries in NZDT

New Zealand

Major Cities in NZDT

AucklandWellingtonChristchurchHamiltonDunedin

Key Facts about NZDT

•NZDT runs from the last Sunday in September to the first Sunday in April.
•NZDT is UTC+13:00 — one of the earliest time offsets used anywhere.
•New Zealand changes its clocks two to three weeks before Australia.
•The Chatham Islands observe UTC+13:45 during their summer time.

Daylight Saving:Yes – switches to NZDT

Learn more about NZDT on Wikipedia

Time Conversion Guide: IRST to NZDT

IRST runs on Iran Standard Time (IRST) at UTC+03:30. NZDT runs on New Zealand Daylight Time (NZDT) at UTC+13:00. That puts IRST 9 hours 30 minutes ahead of NZDT — a difference of +9h 30m at the current offsets.

In practice, when it is 9:00 AM in IRST it is 6:30 PM in NZDT. Midnight in IRST is 9:30 AM in NZDT. Neither zone observes daylight saving time, so the offset between them stays constant all year.

IRST to NZDT time conversion table

IRST (IRST)	NZDT (NZDT)	Day
12:00 AM	9:30 AM	same day
6:00 AM	3:30 PM	same day
7:00 AM	4:30 PM	same day
8:00 AM	5:30 PM	same day
9:00 AM	6:30 PM	same day
12:00 PM	9:30 PM	same day
3:00 PM	12:30 AM	next day
5:00 PM	2:30 AM	next day
6:00 PM	3:30 AM	next day
9:00 PM	6:30 AM	next day

Why people convert IRST to NZDT time

Scheduling a call from IRST to NZDT: a 10:00 AM start in IRST lands at 7:30 PM in NZDT, so you can confirm the slot without doing the arithmetic yourself.
Handling a +9h 30m gap: IRST and NZDT 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 NZDT is 6:30 PM in IRST.
Keeping family and friends in sync: knowing that 8:00 PM in IRST is 5:30 AM in NZDT 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 +9h 30m gap is not.
With a +9h 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 NZDT 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 NZDT (New Zealand Daylight Time)

New Zealand Daylight Time (NZDT) is the summer time zone for New Zealand, one hour ahead of New Zealand Standard Time (NZST, UTC+12:00). It runs from the last Sunday in September to the first Sunday in April, so New Zealand shifts a week or two earlier in spring than Australia. At UTC+13:00, NZDT is among the earliest offsets in the world — only Samoa, Tonga and parts of Kiribati run further ahead at certain times of year. Auckland and Wellington are 13 hours ahead of UTC during NZDT, 12 hours ahead of Sydney, and 18 hours ahead of New York. The Chatham Islands, 45 minutes further east, move to UTC+13:45.

Best time to call between IRST and NZDT

With a +9h 30m offset there is no overlap inside a normal 9 AM – 5 PM day. NZDT opens at 9:00 AM NZDT, which is 6:30 PM in IRST, so real-time calls need an early-morning or late-evening slot on one side.

Business hours overlap

IRST and NZDT have no shared working hours because of the +9h 30m gap. Teams need to alternate early starts or rely on asynchronous handovers.

IRST is 9 hours 30 minutes ahead of NZDT (IRST UTC+03:30 → NZDT UTC+13:00). 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

NZDT

☀ Currently in DST

Standard: UTC+12:00 · DST: UTC+13:00

Clocks fall back on Sat, Apr 3, 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 NZDT?

IRST (IRST, UTC+03:30) is 9 hours 30 minutes ahead of NZDT (NZDT, UTC+13:00). The gap is currently +9h 30m.

How do I convert IRST time to NZDT time?

Add +9h 30m to IRST local time. For example, 9:00 AM in IRST is 6:30 PM in NZDT.

What time is it in NZDT right now?

NZDT uses NZDT at UTC+13:00. Use the live converter at the top of this page — it updates in real time and already accounts for the +9h 30m offset from IRST.