Convert time from IRST to GMT. Enter any time to see the equivalent GMT time, compare current IRST and GMT times side by side, and find overlapping business hours for calls and meetings.
Use this IRST to GMT converter to compare Iran and United Kingdom time, check the 3 hours and 30 minutes gap, and confirm the right slot for calls, handoffs, and deadlines. Good overlap starts around 1:00 PM IRST / 9:30 AM GMT.
Converting between Iran Standard Time and Greenwich Mean 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 Iran Standard Time (UTC +3:30) that you want to convert. Hit "Now" to load the current irst time instantly, or use "+1h" to step forward and compare.
The equivalent Greenwich Mean Time (UTC +0) time appears immediately. Since gmt is 3 hours and 30 minutes behind of irst, most daytime conversions stay on the same calendar day.
Click "Copy Time" to grab the gmt 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 Iran suggests 1:00 PM irst, that's 9:30 AM gmt. This converter shows the overlap so both sides agree on one slot — no back-and-forth.
Late-night irst times can land on a different date in gmt 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 irst (UTC +3:30) and gmt (UTC +0) 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 irst. Convert the event time to gmt so you know exactly when to tune in — with a 3 hours and 30 minutes difference, a morning event in Iran falls during work hours in United Kingdom.
Quick-reference conversion table covering every hour of the day at a glance.
Iran Standard Time to Greenwich Mean Time full day schedule
| Iran Standard Time | Greenwich Mean Time |
|---|---|
| 12:00 AM |
8:30 PM
(previous day)
|
| 1:00 AM |
9:30 PM
(previous day)
|
| 2:00 AM |
10:30 PM
(previous day)
|
| 3:00 AM |
11:30 PM
(previous 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
|
| 10:00 AM |
6:30 AM
|
| 11:00 AM |
7:30 AM
|
| 12:00 PM |
8:30 AM
|
| 1:00 PM |
9:30 AM
|
| 2:00 PM |
10:30 AM
|
| 3:00 PM |
11:30 AM
|
| 4:00 PM |
12:30 PM
|
| 5:00 PM |
1:30 PM
|
| 6:00 PM |
2:30 PM
|
| 7:00 PM |
3:30 PM
|
| 8:00 PM |
4:30 PM
|
| 9:00 PM |
5:30 PM
|
| 10:00 PM |
6:30 PM
|
| 11:00 PM |
7:30 PM
|
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 irst 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 Greenwich Mean Time. Use these pages when scheduling with United Kingdom from a different region.
