Convert time from GMT to IRST. Enter any time to see the equivalent IRST time, compare current GMT and IRST times side by side, and find overlapping business hours for calls and meetings.
Use this GMT to IRST converter to compare United Kingdom and Iran time, check the 3 hours and 30 minutes gap, and confirm the right slot for calls, handoffs, and deadlines. Good overlap starts around 9:00 AM GMT / 12:30 PM IRST.
Converting between Greenwich Mean Time and Iran Standard Time means accounting for a 3 hours and 30 minutes gap — here's how to do it in under 10 seconds with no sign-up.
Pick the date and time in Greenwich Mean Time (UTC +0) that you want to convert. Hit "Now" to load the current gmt time instantly, or use "+1h" to step forward and compare.
The equivalent Iran Standard Time (UTC +3:30) time appears immediately. Since irst is 3 hours and 30 minutes ahead of gmt, most daytime conversions stay on the same calendar day.
Click "Copy Time" to grab the irst result for your calendar or message. Use "+1d" to check how the conversion shifts across dates — useful when Daylight Saving Time changes the gap.
When someone in United Kingdom suggests 9:00 AM gmt, that's 12:30 PM irst. This converter shows the overlap so both sides agree on one slot — no back-and-forth.
Late-night gmt times can land on a different date in irst because of the 3 hours and 30 minutes offset. The converter labels "next day" or "previous day" next to the result so you never send a message a day early or miss a deadline.
The half-hour offset between gmt (UTC +0) and irst (UTC +3:30) already makes mental math tricky — add Daylight Saving Time and the gap can shift further. This converter uses live UTC offsets, so you're always accurate.
Product launches, sports matches, and webinars are often announced in gmt. Convert the event time to irst so you know exactly when to tune in — with a 3 hours and 30 minutes difference, a morning event in United Kingdom falls during work hours in Iran.
Quick-reference conversion table covering every hour of the day at a glance.
Greenwich Mean Time to Iran Standard Time full day schedule
| Greenwich Mean Time | Iran Standard Time |
|---|---|
| 12:00 AM |
3:30 AM
|
| 1:00 AM |
4:30 AM
|
| 2:00 AM |
5:30 AM
|
| 3:00 AM |
6:30 AM
|
| 4:00 AM |
7:30 AM
|
| 5:00 AM |
8:30 AM
|
| 6:00 AM |
9:30 AM
|
| 7:00 AM |
10:30 AM
|
| 8:00 AM |
11:30 AM
|
| 9:00 AM |
12:30 PM
|
| 10:00 AM |
1:30 PM
|
| 11:00 AM |
2:30 PM
|
| 12:00 PM |
3:30 PM
|
| 1:00 PM |
4:30 PM
|
| 2:00 PM |
5:30 PM
|
| 3:00 PM |
6:30 PM
|
| 4:00 PM |
7:30 PM
|
| 5:00 PM |
8:30 PM
|
| 6:00 PM |
9:30 PM
|
| 7:00 PM |
10:30 PM
|
| 8:00 PM |
11:30 PM
|
| 9:00 PM |
12:30 AM
(next day)
|
| 10:00 PM |
1:30 AM
(next day)
|
| 11:00 PM |
2:30 AM
(next day)
|
UK / Ireland / Iceland / Portugal / West Africa. Business hours 9 AM – 5:30 PM GMT typically. Note: London is on GMT in winter, BST (GMT+1) in summer — but "GMT" gets used loosely all year in scheduling contexts. Financial-services London anchors the European trading day.
Explore more gmt conversions for major business and travel corridors. Each page includes a 24-hour chart, time difference summary, and meeting overlap guidance.
Find the time difference from any major zone into Iran Standard Time. Use these pages when scheduling with Iran from a different region.
