What is the time difference between IRST and NZST?

New Zealand Standard Time (NZST) is 9 hours and 30 minutes ahead of Iran Standard Time (IRST). IRST uses a UTC offset of UTC+3:30, while NZST uses UTC+13. For example, when it's 9:00 AM in IRST, it's 6:30 PM in NZST. Note that this difference may shift by one hour during daylight saving time transitions if NZST observes DST. Use the conversion table above to see the exact time for each hour of the day.

How do I convert IRST to NZST?

To convert IRST to NZST, add 9 hours and 30 minutes to the IRST time. For example, 9:00 AM IRST is 6:30 PM NZST, and 5:00 PM IRST is 2:30 AM NZST. Keep in mind that during daylight saving time transitions, the offset between these timezones may temporarily change by one hour. You can also use the interactive converter above for quick, accurate results.

What time is it in NZST when it's noon in IRST?

When it's 12:00 PM (noon) in IRST, it's 9:30 PM in NZST. This is because NZST is 9 hours and 30 minutes ahead of IRST. Similarly, when it's 6:00 PM in IRST, it's 3:30 AM in NZST. During daylight saving time transitions, these times may shift by one hour, so always verify the current offset. The color-coded conversion table above shows every hour mapped between both timezones.

How many hours ahead is NZST from IRST?

NZST is 9 hours and 30 minutes ahead of IRST. This means when it's 9:00 AM in IRST, it's 6:30 PM in NZST, and when it's midnight in IRST, it's 9:30 AM in NZST. The exact difference can vary by one hour during daylight saving time transitions. The conversion table above provides a complete hour-by-hour mapping.

Is NZST ahead or behind IRST?

NZST is ahead of IRST by 9 hours and 30 minutes. Clocks in NZST show a later time than IRST, meaning the day starts earlier in NZST relative to IRST. For example, when it's morning in IRST, it's already afternoon or evening in NZST. This gap may change by one hour during DST transitions.

Does IRST observe daylight saving time?

No, Iran Standard Time does not observe daylight saving time. The UTC offset of UTC+3:30 remains the same year-round, which simplifies time conversions. Regions using IRST keep their clocks unchanged regardless of the season.

Does NZST observe daylight saving time?

Yes, New Zealand Standard Time observes daylight saving time. During DST, the abbreviation changes to NZDT and clocks move forward by one hour, typically in spring. Clocks then fall back in autumn, returning to standard NZST time. This means the UTC offset for NZST shifts between two values depending on the season. Check our DST change calendar for exact transition dates that may affect your IRST to NZST conversions.

What is the best time to call from IRST to NZST?

The best time for a call between IRST and NZST is during overlapping business hours (9 AM – 5 PM) in both timezones. To reach someone in NZST during their work day, call between 11:30 PM and 7:30 AM your IRST time. Avoid calling too early or late, as the 9 hours and 30 minutes difference means your evening could be their late night. Check the color-coded conversion table above — green hours indicate business hours in both zones, making it easy to find the ideal time.

When does daylight saving time change in NZST?

Daylight saving time transitions vary by year and region. New Zealand Standard Time observes DST, which typically shifts clocks forward by one hour in spring ("spring forward") and back in fall ("fall back"). During these transition periods, the time difference between IRST and NZST may temporarily change by one hour, which can cause confusion for scheduled meetings or calls. It's important to double-check your conversions around transition dates, especially if the two timezones switch on different dates. Check our DST change calendar for exact transition dates in the current year.

Do IRST and NZST ever have the same time?

No, IRST and NZST never show the same time because their base UTC offsets are different. However, because NZST observes daylight saving time and IRST does not, the time difference between them changes by one hour during DST transitions. This means the gap narrows or widens depending on the season, but the two clocks never align. Always verify the current offset around DST transition dates to avoid scheduling errors.

IRST to NZST Converter

Convert Iran Standard Time to New Zealand Standard Time. See the hour-by-hour conversion table below.

Upcoming DST Change

New Zealand Time (NZDT) will fall back on April 5. Clocks will shift by 1 hour (NZDT → NZST).

View all DST changes

Timezone Details

Tehran

7:17 PM

Thursday, April 2, 2026

Tehran (UTC+03:30)

New Zealand Standard Time

4:47 AM

Friday, April 3, 2026

NZDT (UTC+13:00)

Difference: +9h 30m

NZDT DST: Yes (NZDT)

24-Hour Overview

Tehran — 24-hour overview

12a12a

3a3a

6a6a

9a9a

10a

11a

12p12p

3p3p

6p6p

9p9p

10p

11p

NightMorningBusinessEvening

NZDT — 24-hour overview

9a9a

10a

11a

12p12p

3p3p

6p6p

9p9p

10p

11p

12a12a

3a3a

6a6a

NightMorningBusinessEvening

Frequently Asked Questions

Related Conversions

NZST to IRST

Cities in These Timezones

IRST Cities

Tehran

NZST Cities

Auckland Christchurch Wellington

More Tools

Compare IRST & NZST Plan a Meeting (IRST & NZST)See on Map

Learn More

How Time Zones Work Understanding DST Timezone Abbreviations

External Resources

New Zealand Standard Time on Wikipedia IANA Time Zone Database