IRST — Iran Standard Time
See what IRST means, where it is used, and how to compare Iran Standard Time with other time zones worldwide.
How to Convert IRST to Other Time Zones
Open the IRST converter page: Go to https://www.xconvert.com/time-converter/irst-time-zone to load the visual comparison grid with Iran Standard Time (IRST) already shown at UTC+3:30. This page is useful when you need to line up a call with contacts in Iran, check a travel connection through Tehran, or coordinate work between an Iran-based team and offices in Europe, Asia, or North America.
Add the cities you want to compare: Click + Add City and search for cities such as London, Dubai, and New York to compare IRST against major finance, trade, and business hubs. For example, Dubai is a common regional business reference in the Gulf, London matters for banking and international services, and New York is relevant for US clients, media, and multinational teams working across large time differences.
Drag across the grid to select a meeting window: Click Select if needed, then drag across the IRST row to highlight a time range in purple; you can resize it with the left and right handles or move the whole block by dragging the center. For example, if you drag 9:00 AM to 11:00 AM IRST, that corresponds to 5:30 AM to 7:30 AM in London during standard time, 8:30 AM to 10:30 AM in Dubai, and 1:30 AM to 3:30 AM in New York during Eastern Standard Time, showing immediately why an Iran morning meeting usually works better for the Gulf than for the US East Coast.
Export and share the selected time: Once your time range is highlighted, use the export options for ICS download, Google Calendar, Gmail, Copy to clipboard, or Share link. This is especially helpful when sending a confirmed slot to a distributed team, because the exported event preserves the time-zone conversion so each participant sees the meeting in their own local time automatically.
About Iran Standard Time (IRST)
IRST stands for Iran Standard Time. Its exact offset is UTC+3:30, which means local time in IRST is 3 hours and 30 minutes ahead of Coordinated Universal Time; when it is 12:00 UTC, it is 3:30 PM IRST.
Iran Standard Time is used by Iran as its national standard time. The most important reference city is Tehran, the capital and largest city of Iran, with a metropolitan population in the millions and serving as the country’s main center for government, finance, aviation, higher education, and technology.
The half-hour offset is a key detail because IRST does not align with the more common whole-hour time zones such as UTC+3 or UTC+4. In practical scheduling terms, IRST is 30 minutes ahead of Arabia Standard Time (UTC+3) used in cities like Riyadh, 30 minutes behind Gulf Standard Time (UTC+4) used in Dubai and Abu Dhabi, 1 hour ahead of Central European Time (UTC+1) during European winter, and 8 hours 30 minutes ahead of Eastern Standard Time (UTC-5) during US winter.
For international coordination, that half-hour difference matters in real workflows. A meeting at 2:00 PM in Tehran happens at 1:30 PM in Riyadh, 2:30 PM in Dubai, 10:00 AM in Berlin during standard time, and 5:30 AM in New York during standard time, so teams working with Iran often need a visual overlap check rather than relying on rough mental conversion.
IRST and Daylight Saving Time
Iran Standard Time is currently listed here with DST: false, which means IRST itself does not observe daylight saving time in this context and remains at UTC+3:30 year-round. That also means there is no seasonal switch to a daylight variant such as a summer offset on this page.
For the current year, 2026, there are no DST transition dates for IRST under this specification. In practical terms, there is no spring clock change and no autumn clock rollback, so if you schedule recurring events in IRST, the Iran side stays fixed at UTC+3:30 while other countries may still move forward or backward seasonally.
This becomes important when comparing IRST with regions that do use DST. For example, the time difference between IRST and London is 3 hours 30 minutes when the UK is on GMT (UTC+0), but only 2 hours 30 minutes when the UK is on British Summer Time (UTC+1); similarly, the gap between IRST and New York changes depending on whether the US is on EST (UTC-5) or EDT (UTC-4).
Frequently Asked Questions
What does IRST stand for?
IRST stands for Iran Standard Time. It is the standard civil time used for Iran and is set at UTC+3:30, meaning it runs three and a half hours ahead of UTC.
Is IRST the same as GMT?
No, IRST is not the same as GMT. GMT is UTC+0, while IRST is UTC+3:30, so Iran Standard Time is 3 hours and 30 minutes ahead of GMT; when it is 9:00 AM GMT, it is 12:30 PM IRST.
Which cities use IRST?
The main city associated with IRST is Tehran, which is the political and economic center of Iran. Other major Iranian cities such as Mashhad, Isfahan, Shiraz, Tabriz, and Karaj also follow the same national standard time, making IRST the practical reference for scheduling across the country.
What is the UTC offset for IRST?
The UTC offset for IRST is +3:30. This means you add 3 hours and 30 minutes to UTC to get Iran Standard Time, so 6:00 UTC becomes 9:30 AM IRST.
When does IRST change?
Based on this page’s specification, IRST does not change for daylight saving time and remains fixed at UTC+3:30 throughout the year. For 2026, there are no DST start or end dates to track, which simplifies recurring scheduling from the Iran side even though other countries may still shift seasonally.
Is IRST ahead of Dubai or behind Dubai?
IRST is 30 minutes behind Dubai. Dubai uses Gulf Standard Time (UTC+4), so when it is 10:00 AM in Dubai, it is 9:30 AM in IRST.
How far ahead is IRST from New York?
The difference depends on the US season because New York changes clocks while IRST on this page does not. IRST is 8 hours 30 minutes ahead of New York during Eastern Standard Time (UTC-5) and 7 hours 30 minutes ahead during Eastern Daylight Time (UTC-4), so a 6:00 PM meeting in Tehran would be 9:30 AM in New York during EST or 10:30 AM during EDT.
Why is IRST a half-hour time zone?
IRST uses a 30-minute offset, which is less common than whole-hour offsets but is fully valid in global timekeeping. This matters in business scheduling, aviation planning, and calendar coordination because a quick estimate can easily be wrong by 30 minutes if you assume Iran follows a standard whole-hour offset like UTC+3 or UTC+4.