Convert GMT to IRST — Time Difference Between Greenwich Mean Time and Iran Standard Time
Drag the slider or click the time display to type a specific hour and instantly convert GMT to IRST — Iran Standard Time is 3:30 hours ahead of Greenwich Mean Time. Scroll down to browse the full GMT to IRST conversion table, check what time 9 AM, 10 AM, 11 AM, or 12 PM in London is in Tehran, and use the date picker to compare times on any day for accurate scheduling.
GMT
Greenwich Mean Time
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IRST
Iran Standard Time
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GMT to IRST Time Zone Difference — Hour-by-Hour Conversion Table
Scan each row to find what time any hour in London is in Tehran — tap the arrows to jump between days, click "Today" to reset, and use the color-coded bands to quickly spot overlapping work hours, early mornings, and late nights at a glance.
| GMT (London) | IRST (Tehran) |
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How to Convert GMT to IRST
Drag the slider on the GMT timeline to pick your time — the IRST time updates instantly. You can also click the time display to type a specific hour or pick one from the 15-minute interval dropdown, and use the date picker to check a different day.
What Is the Time Difference Between GMT and IRST?
Iran Standard Time (IRST) is 3:30 hours ahead of Greenwich Mean Time (GMT). To convert, add 3:30 hours — for example, 9:00 AM GMT is 12:30 PM IRST.
What Time Is It Now in London?
What Time Is It Now in Tehran?
GMT to IRST Quick Reference
GMT to IRST Meeting Planner
Use the color-coded table above to find overlapping work hours between London and Tehran. Amber rows mark daytime hours — pick a slot that falls in amber on both sides for a meeting that works for everyone.
Why Trust This GMT to IRST Converter?
Timezoney uses the IANA Time Zone Database — the same source that powers your phone and computer — so every conversion handles daylight saving transitions and half-hour offsets automatically.
Greenwich Mean Time
- Abbreviation
- GMT
- UTC Offset
- UTC+0:00
- City
- London
- Country
- United Kingdom
Iran Standard Time
- Abbreviation
- IRST
- UTC Offset
- UTC+3:30
- City
- Tehran
- Country
- Iran