IRST (Iran Standard Time) is UTC+3:30, all year. It is used in Tehran.
Where and when IRST is used
| IANA time zone | Uses IRST | Main cities |
|---|---|---|
| Asia/Tehran | All year | Tehran, Mashhad, Isfahan |
IRST to UTC, GMT and other zones
Because IRST always means UTC+3:30, each row below is a fixed difference. Check the date only to know whether a place is on IRST at all.
| Zone | UTC offset | When it is 12:00 IRST |
|---|---|---|
| UTC | UTC+0 | 8:30 AM |
| GMT | UTC+0 | 8:30 AM |
| EST | UTC−5 | 3:30 AM |
| EDT | UTC−4 | 4:30 AM |
| CST | UTC−6 | 2:30 AM |
| MST | UTC−7 | 1:30 AM |
| PST | UTC−8 | 12:30 AM |
| CET | UTC+1 | 9:30 AM |
| CEST | UTC+2 | 10:30 AM |
| EET | UTC+2 | 10:30 AM |
| MSK | UTC+3 | 11:30 AM |
| GST | UTC+4 | 12:30 PM |
| IST | UTC+5:30 | 2:00 PM |
| ICT | UTC+7 | 3:30 PM |
| JST | UTC+9 | 5:30 PM |
| AEST | UTC+10 | 6:30 PM |
| AEDT | UTC+11 | 7:30 PM |
Plan around the time in IRST
- Convert a time to or from IRST: pick a date and time and see it in every city on your list.
- Add Tehran to your world clock to keep it next to your own time.
- Find a meeting time that falls inside office hours in IRST and the other cities you work with.
- Open a full-screen clock for your own time zone.
Frequently asked questions
What is IRST in UTC?
IRST is UTC+3:30. To get UTC, subtract 3 hours 30 minutes from IRST time.
What time is 12:00 IRST in UTC?
12:00 IRST is 8:30 AM UTC.
Time zone rules: IANA tz database, version 2026e. Place names and coordinates: GeoNames. Sunrise and sunset are calculated from the coordinates and can differ by a minute or two from local almanacs.