What is the time difference between IRST and GST?

Gulf Standard Time (GST) is 0 hours and 30 minutes ahead of Iran Standard Time (IRST). IRST uses a UTC offset of UTC+3:30, while GST uses UTC+4. For example, when it's 9:00 AM in IRST, it's 9:30 AM in GST. This difference remains constant year-round since neither timezone observes daylight saving time. Use the conversion table above to see the exact time for each hour of the day.

How do I convert IRST to GST?

To convert IRST to GST, add 0 hours and 30 minutes to the IRST time. For example, 9:00 AM IRST is 9:30 AM GST, and 5:00 PM IRST is 5:30 PM GST. Since neither timezone observes DST, this conversion stays the same all year. You can also use the interactive converter above for quick, accurate results.

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

When it's 12:00 PM (noon) in IRST, it's 12:30 PM in GST. This is because GST is 0 hours and 30 minutes ahead of IRST. Similarly, when it's 6:00 PM in IRST, it's 6:30 PM in GST. This relationship is constant throughout the year. The color-coded conversion table above shows every hour mapped between both timezones.

How many hours ahead is GST from IRST?

GST is 0 hours and 30 minutes ahead of IRST. This means when it's 9:00 AM in IRST, it's 9:30 AM in GST, and when it's midnight in IRST, it's 12:30 AM in GST. This offset is constant throughout the year since neither timezone uses daylight saving time. The conversion table above provides a complete hour-by-hour mapping.

Is GST ahead or behind IRST?

GST is ahead of IRST by 0 hours and 30 minutes. Clocks in GST show a later time than IRST, meaning the day starts earlier in GST relative to IRST. For example, when it's morning in IRST, it's later in the morning in GST. This difference stays the same year-round.

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 GST observe daylight saving time?

No, Gulf Standard Time does not observe daylight saving time. The UTC offset of UTC+4 remains the same year-round, making time conversions to GST more predictable. Countries and regions in this timezone keep their clocks unchanged regardless of the season.

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

The best time for a call between IRST and GST is during overlapping business hours (9 AM – 5 PM) in both timezones. To reach someone in GST during their work day, call between 8:30 AM and 4:30 PM your IRST time. Avoid calling too early or late, as the 0 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.

Do IRST and GST ever have the same time?

No, IRST and GST are always 0 hours and 30 minutes apart and never display the same clock time simultaneously. Neither timezone observes DST, so the difference is constant year-round with no seasonal variation. The 0 hours and 30 minutes offset is determined by their fixed positions relative to the Prime Meridian (UTC). You can always rely on this consistent difference when planning across these timezones.

IRST to GST Converter

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

Timezone Details

Tehran

2:53 AM

Friday, April 3, 2026

Tehran (UTC+03:30)

Gulf Standard Time

3:23 AM

Friday, April 3, 2026

GST (UTC+04:00)

Difference: +0h 30m

GST DST: No

24-Hour Overview

Tehran — 24-hour overview

12a12a

3a3a

6a6a

9a9a

10a

11a

12p12p

3p3p

6p6p

9p9p

10p

11p

NightMorningBusinessEvening

GST — 24-hour overview

12a12a

3a3a

6a6a

9a9a

10a

11a

12p12p

3p3p

6p6p

9p9p

10p

11p

NightMorningBusinessEvening

Frequently Asked Questions

Related Conversions

GST to IRST

Cities in These Timezones

IRST Cities

Tehran

GST Cities

Dubai Abu Dhabi

More Tools

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

Learn More

How Time Zones Work Understanding DST Timezone Abbreviations

External Resources

Gulf Standard Time on Wikipedia IANA Time Zone Database