IRST to UTC Time Converter
UTC is 3 hours and 30 minutes behind IRST. IRST is UTC+3:30, and UTC is the zero point, UTC±00:00.
Best Time to Call Between IRST and UTC
Both zones are inside normal business hours between 1:00 PM and 5:00 PM IRST — that's 9:30 AM to 1:30 PM UTC. That's a 4-hour window.
both at work IRST only UTC only neither — hours along the strip are IRST.
Common Times Converted
IRST on the left, UTC on the right.
IRST to UTC: Full 24-Hour Conversion Table
Shaded rows are working hours; the darker shade marks the hours when both zones are at work.
| IRST | UTC | Working hours |
|---|---|---|
| 12:00 AM | 8:30 PM prev day | — |
| 1:00 AM | 9:30 PM prev day | — |
| 2:00 AM | 10:30 PM prev day | — |
| 3:00 AM | 11:30 PM prev day | — |
| 4:00 AM | 12:30 AM | — |
| 5:00 AM | 1:30 AM | — |
| 6:00 AM | 2:30 AM | — |
| 7:00 AM | 3:30 AM | — |
| 8:00 AM | 4:30 AM | — |
| 9:00 AM | 5:30 AM | IRST only |
| 10:00 AM | 6:30 AM | IRST only |
| 11:00 AM | 7:30 AM | IRST only |
| 12:00 PM | 8:30 AM | IRST only |
| 1:00 PM | 9:30 AM | Both zones |
| 2:00 PM | 10:30 AM | Both zones |
| 3:00 PM | 11:30 AM | Both zones |
| 4:00 PM | 12:30 PM | Both zones |
| 5:00 PM | 1:30 PM | UTC only |
| 6:00 PM | 2:30 PM | UTC only |
| 7:00 PM | 3:30 PM | UTC only |
| 8:00 PM | 4:30 PM | UTC only |
| 9:00 PM | 5:30 PM | — |
| 10:00 PM | 6:30 PM | — |
| 11:00 PM | 7:30 PM | — |
What IRST and UTC Actually Are
IRST — Iran Standard Time
Tehran, Mashhad, Isfahan. Standing at UTC+3:30 as written, and the region does not change its clocks, so that offset holds all year. Iran abolished daylight saving in 2022, so the half-hour offset now holds all year.
Iran abolished daylight saving in 2022. Its half-hour offset is a deliberate compromise between the solar times of its western and eastern borders.
UTC — Coordinated Universal Time
The global reference standard. Aviation, computing and science run on it. Standing at UTC as written, and the region does not change its clocks, so that offset holds all year.
UTC is not a place. It is a computed standard, kept within a second of mean solar time at Greenwich by atomic clocks, and it is the reference every other zone is defined against.
What This Means in Practice
Expect times on the half hour
IRST sits on a 30-minute offset rather than a whole hour, so a round number on one side is never a round number on the other. A 9:00 meeting becomes 30 minutes past the hour, which is exactly the detail calendar invitations get wrong when someone converts in their head.
A gap you can rely on
Neither region changes its clocks, so this difference holds every day of the year. A recurring meeting booked once stays correct — worth knowing, because most cross-border pairs cannot say that.
Major Cities in Each Zone
Cities on IRST
Frequently Asked Questions
What is the time difference between IRST and UTC?
UTC is 3 hours and 30 minutes behind IRST.
What is 9:00 AM IRST in UTC?
9:00 AM IRST is 5:30 AM UTC.
What are the best hours to schedule a call between IRST and UTC?
Between 1:00 PM and 5:00 PM IRST, which is 9:30 AM to 1:30 PM UTC. Both sides are inside normal business hours through that window.
Does the difference between IRST and UTC change during the year?
No. Neither region changes its clocks, so this gap is fixed all year round.
Does IRST always mean Iran Standard Time?
Iran abolished daylight saving in 2022, so the half-hour offset now holds all year.