IRDT — Iran Daylight Time

How to Convert IRDT to Other Time Zones

1. Open the IRDT converter page: Go to https://www.xconvert.com/time-converter/irdt-time-zone to load the visual comparison grid with Iran Daylight Time (IRDT) already shown as the base time zone. This page is useful when you need to line up a call, shipment update, or engineering handoff involving Iran’s daylight time, especially because IRDT runs at UTC+4:30, a half-hour offset that can easily cause mistakes if you convert mentally.

2. Add comparison cities with the + Add City button: Click “+ Add City” and add cities such as London, Dubai, and New York to compare IRDT against major finance, aviation, and business hubs. For example, London matters for banking and trade, Dubai is a major regional logistics and airline connection point, and New York is relevant for multinational teams and clients working across North American business hours.

3. Drag on the grid to select a meeting window: Click “Select” if needed, then drag across the IRDT row to highlight a time range in purple, such as 9:00 AM to 11:00 AM IRDT. That selection lets you instantly see the equivalent time in other rows—for example, 9:00 AM IRDT is 5:30 AM UTC, 8:30 AM in Dubai (UTC+4), and 1:30 AM in New York during Eastern Daylight Time (UTC-4), which shows why an Iran morning meeting is usually too early for the U.S. East Coast but practical for Gulf-region coordination.

4. Export or share the selected time: After selecting a range, use the export options for ICS download, Google Calendar, Gmail, Copy to clipboard, or Share link. This is especially helpful if you are scheduling a cross-border operations call, because an ICS file or Google Calendar link will place the event in each participant’s local time automatically, reducing errors around the unusual :30-minute offset used by IRDT.

About Iran Daylight Time (IRDT)

IRDT stands for Iran Daylight Time, the daylight saving time designation historically associated with Iran when clocks were set one hour ahead of standard time. Its exact offset is UTC+4:30, meaning IRDT is 4 hours 30 minutes ahead of Coordinated Universal Time; when it is 12:00 noon UTC, it is 4:30 PM in IRDT.

IRDT is tied to Iran, whose standard time is IRST (Iran Standard Time, UTC+3:30). During periods when daylight saving time was observed, clocks moved forward by one hour from IRST to IRDT, creating the UTC+4:30 offset. The country’s largest city and main commercial center is Tehran, with a population of roughly 9 million within the city and over 15 million in the metropolitan area, and Tehran is the city most commonly associated with this time designation in business scheduling, aviation timetables, and regional coordination.

IRDT is not a whole-hour time zone, which makes it important for international planning involving markets, travel, and remote work. For example, IRDT is 30 minutes ahead of Gulf cities such as Dubai and Abu Dhabi (UTC+4), 1 hour ahead of Moscow during standard UTC+3 periods, and 2 hours 30 minutes ahead of Central European Summer Time (UTC+2). That means when it is 9:00 AM in IRDT, it is 8:30 AM in Dubai, 6:30 AM in Berlin during summer, and 5:30 AM in London during British Summer Time.

The same UTC offset, UTC+4:30, is also used by the abbreviation AFT, which stands for Afghanistan Time. However, AFT is a standard time used year-round in Afghanistan, while IRDT refers specifically to Iran’s daylight time usage, so the abbreviations are not interchangeable in historical or legal scheduling contexts.

IRDT and Daylight Saving Time

IRDT is the daylight saving time version of Iran’s civil time, and it switches from IRST (UTC+3:30) to IRDT (UTC+4:30) when daylight saving is in effect. Under the historical DST system, clocks moved forward by 1 hour, so a local time like 12:00 AM IRST became 1:00 AM IRDT, affecting business opening hours, domestic transport schedules, and international call planning.

For the current year, 2026, Iran does not observe daylight saving time in practice, because the country abolished seasonal clock changes beginning in 2022. As a result, there are no 2026 DST transition dates in Iran, and official civil time remains on Iran Standard Time (IRST, UTC+3:30) throughout the year rather than switching to IRDT. This is important for users searching IRDT data, because many older systems, archived timestamps, and historical records still reference IRDT even though current scheduling in Iran generally stays on standard time.

Historically, when Iran did observe daylight saving time, the switch commonly aligned with the Persian calendar and was associated with Nowruz-season administrative changes, rather than the March/October or March/November patterns used in Europe and North America. If you are reviewing older contracts, flight records, server logs, or calendar invites from years before the DST abolition, you should verify whether the timestamp was recorded in IRST (UTC+3:30) or IRDT (UTC+4:30), because a one-hour error can affect legal deadlines, meeting records, and transport coordination.

This distinction matters in real-world use. A company comparing archived Tehran office hours with current operations may find that a 9:00 AM timestamp in historical IRDT corresponds differently to London, Frankfurt, or Dubai than a 9:00 AM timestamp in today’s year-round IRST. For finance, compliance, and distributed software teams, confirming whether a record uses historical IRDT or present-day IRST avoids mistakes in audit trails and cross-border communications.

Frequently Asked Questions

What does IRDT stand for?

IRDT stands for Iran Daylight Time. It is the daylight saving time label historically used for Iran when clocks were advanced to UTC+4:30, one hour ahead of Iran Standard Time (IRST, UTC+3:30).

Is IRDT the same as GMT?

No, IRDT is not the same as GMT. GMT is effectively UTC+0, while IRDT is UTC+4:30, so IRDT is 4 hours 30 minutes ahead of GMT; when it is 10:00 AM GMT, it is 2:30 PM IRDT.

Which cities use IRDT?

The main city associated with IRDT is Tehran, Iran’s capital and largest urban center. Other major Iranian cities such as Mashhad, Isfahan, Shiraz, Tabriz, and Karaj would also have followed the same national daylight time rules when IRDT was in effect, because Iran used a single national time standard rather than separate city-based zones.

What is the UTC offset for IRDT?

The UTC offset for IRDT is UTC+4:30. That means local IRDT time is always 4 hours and 30 minutes ahead of UTC, so 6:00 PM IRDT equals 1:30 PM UTC.

When does IRDT change?

Historically, IRDT changed when Iran moved between IRST (UTC+3:30) and IRDT (UTC+4:30) for daylight saving time. However, in the current year 2026, Iran does not switch to IRDT, because the country no longer applies seasonal DST changes, so there are no active 2026 transition dates for IRDT in current civil use.

Is IRDT the same as AFT?

IRDT and AFT share the same numeric offset of UTC+4:30, but they are not the same time zone label. AFT refers to Afghanistan Time, used as standard time in Afghanistan, while IRDT refers to Iran’s historical daylight saving time, so the abbreviations point to different countries and different timekeeping contexts.

Is IRDT currently used in Iran?

In current practical scheduling, Iran uses IRST (UTC+3:30) year-round, not IRDT. IRDT still appears in historical data, legacy software, archived calendar entries, and some time zone references, so it remains relevant when interpreting older timestamps or systems that have not been updated.

How far ahead is IRDT compared with UTC and Dubai?

IRDT is 4 hours 30 minutes ahead of UTC and 30 minutes ahead of Dubai, which uses Gulf Standard Time (UTC+4). So if it is 9:00 AM in Dubai, it is 9:30 AM in IRDT, and if it is 12:00 noon UTC, it is 4:30 PM in IRDT.