Convert Iran Standard Time to Greenwich Mean Time
Instantly convert Iran Standard Time (IRST) to Greenwich Mean Time (GMT) with our free online calculator.
Iran Standard Time
08:50:48 AM
Wed, Jun 24 (IRST)
Greenwich Mean Time
05:20:48 AM
Wed, Jun 24 (GMT)
Convert a Specific Time
24-Hour Comparison
| IRST | GMT |
|---|---|
| 12:00 AM | 8.5:00 PM(-1d) |
| 1:00 AM | 9.5:00 PM(-1d) |
| 2:00 AM | 10.5:00 PM(-1d) |
| 3:00 AM | 11.5:00 PM(-1d) |
| 4:00 AM | 0.5:00 AM |
| 5:00 AM | 1.5:00 AM |
| 6:00 AM | 2.5:00 AM |
| 7:00 AM | 3.5:00 AM |
| 8:00 AM | 4.5:00 AM |
| 9:00 AM | 5.5:00 AM |
| 10:00 AM | 6.5:00 AM |
| 11:00 AM | 7.5:00 AM |
| 12:00 PM | 8.5:00 AM |
| 1:00 PM | 9.5:00 AM |
| 2:00 PM | 10.5:00 AM |
| 3:00 PM | 11.5:00 AM |
| 4:00 PM | 0.5:00 PM |
| 5:00 PM | 1.5:00 PM |
| 6:00 PM | 2.5:00 PM |
| 7:00 PM | 3.5:00 PM |
| 8:00 PM | 4.5:00 PM |
| 9:00 PM | 5.5:00 PM |
| 10:00 PM | 6.5:00 PM |
| 11:00 PM | 7.5:00 PM |
How to Convert Iran Standard Time to Greenwich Mean Time
Formula
To convert Iran Standard Time (IRST) to Greenwich Mean Time (GMT): Convert IRST to GMT
About Iran Standard Time (IRST)
Iran Standard Time (IRST, IANA: Asia/Tehran) is the civil time of the Islamic Republic of Iran, set at UTC+3:30 — one of the world's few 30-minute-offset time zones. IRST observes Daylight Saving Time (switching to IRDT = UTC+4:30) from the last Wednesday of the Iranian month of Farvardin (~March 22) to the last Wednesday of Shahrivar (~September 22) per Iranian government calendar (the country abolished DST in 2022 then partially reinstated it for energy savings — the schedule is subject to change by Iranian Parliament Majlis decree). The 30-minute offset is preserved because Iran's central meridian is approximately 52.5°E, between UTC+3 and UTC+4 standard zones, and the Iranian Solar Hijri calendar has its own astronomical traditions for time-keeping. IRST serves approximately 88 million Iranian people across 31 provinces. Major cities: Tehran (8.7M city, 13M metro — capital), Mashhad (3.1M), Isfahan (2.2M), Karaj (1.6M), Shiraz (1.6M), Tabriz (1.6M), Qom (1.2M). Other 30/45-minute offset zones: India (UTC+5:30), Nepal (UTC+5:45), Myanmar (UTC+6:30), Newfoundland (UTC-3:30), Afghanistan (UTC+4:30), Marquesas (UTC-9:30). Affects: Tehran Stock Exchange (TSE) trading, Iranian Solar Hijri New Year Nowruz celebrations.
About Greenwich Mean Time (GMT)
Greenwich Mean Time (GMT, IANA: Europe/London) is the historic and current civil time of the United Kingdom (during winter), Ireland (during winter), Portugal mainland (during winter), Iceland (year-round), and most West African countries. GMT is set at UTC+0 — the time on the Prime Meridian (0° longitude) running through the Royal Observatory in Greenwich, southeast London. Established as the global time reference by the 1884 International Meridian Conference in Washington DC, GMT served as the world's primary civil-time reference from 1884 until 1972 when UTC (Coordinated Universal Time) was adopted as the new precision standard. The UK switches from GMT to British Summer Time (BST = UTC+1) at 01:00 GMT on the last Sunday of March and back to GMT at 02:00 BST on the last Sunday of October per EU Directive 2000/84/EC (UK retained this schedule after Brexit). GMT affects: London Stock Exchange (LSE) trading hours, BBC World Service broadcast time-stamps, all aviation NOTAMs and weather METARs which use UTC = GMT, and ICAO + IMO worldwide maritime/aviation coordination.