IRT to GMT Time Converter

Convert Iran Standard Time (IRT) to Greenwich Mean Time (GMT). Both time zones are shown live below; current offset between them is 2h 30m behind.

Tehran · Iran Standard Time
18:08:47
Wednesday, May 13, 2026
GMT+3:30 · UTC+03:30
London · Greenwich Mean Time
15:38:47
Wednesday, May 13, 2026
GMT+1 · UTC+01:00

Convert a specific time

From: IRT (Tehran)
To: GMT (London)
--:--

Daylight Saving status right now

IRT (Iran Standard Time)
Observes DST
No
GMT (Greenwich Mean Time)
Observes DST
Yes
In DST right now
Yes
Next fall back
2026-10-25
Offset shift
UTC+01:00 → UTC+00:00

Heads up: GMT observes DST while IRT does not. The 2.5-hour difference shown above will shift by one hour when GMT starts or ends DST.

When can IRT and GMT meet?

00
01
02
03
04
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09
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IRT
GMT
Both zones in working hours (9am-5pm)
One zone working
Off-hours
Columns are hours of the day in Tehran (IRT). Each row shows the local working-hours state in that zone for the same moment in time.
5 hours of overlap during standard 9am-5pm working hours.
Best meeting window: 12:00–16:00 IRT (09:30–13:30 GMT).

Hour-by-hour IRT to GMT conversion table

IRT time (Tehran)GMT time (London)Status
00:00 Wed21:30 TueOff-hours both sides
01:00 Wed22:30 TueOff-hours both sides
02:00 Wed23:30 TueOff-hours both sides
03:00 Wed00:30 WedOff-hours both sides
04:00 Wed01:30 WedOff-hours both sides
05:00 Wed02:30 WedOff-hours both sides
06:00 Wed03:30 WedOff-hours both sides
07:00 Wed04:30 WedOff-hours both sides
08:00 Wed05:30 WedOff-hours both sides
09:00 Wed06:30 WedIRT working
10:00 Wed07:30 WedIRT working
11:00 Wed08:30 WedIRT working
12:00 Wed09:30 WedBoth at work
13:00 Wed10:30 WedBoth at work
14:00 Wed11:30 WedBoth at work
15:00 Wed12:30 WedBoth at work
16:00 Wed13:30 WedBoth at work
17:00 Wed14:30 WedGMT working
18:00 Wed15:30 WedGMT working
19:00 Wed16:30 WedGMT working
20:00 Wed17:30 WedOff-hours both sides
21:00 Wed18:30 WedOff-hours both sides
22:00 Wed19:30 WedOff-hours both sides
23:00 Wed20:30 WedOff-hours both sides

Times computed for today in each zone using the IANA time zone database. The conversion accounts for daylight saving time wherever applicable.

About these time zones

Iran Standard Time (IRT)
IANA identifier
Asia/Tehran
Current UTC offset
UTC+03:30
Current abbreviation
GMT+3:30
Major cities in this zone
TehranIsfahan
Greenwich Mean Time (GMT)
IANA identifier
Europe/London
Current UTC offset
UTC+01:00
Current abbreviation
GMT+1
Major cities in this zone
LondonManchesterEdinburghBirmingham

Sun today in Tehran and London

Tehran
Sunrise
05:02
Sunset
19:01
Solar noon
12:02
Daylight
13h 58m
London
Sunrise
05:13
Sunset
20:43
Solar noon
12:58
Daylight
15h 29m

Related converters

GMT to IRT (reverse)IRT to ESTIRT to PSTIRT to UTCIRT to CETIRT to ISTEST to GMTPST to GMTUTC to GMTCET to GMTIST to GMT
Looking for local time? See time in Tehran or time in London.

Frequently asked questions

What is the time difference between IRT and GMT right now?+
GMT (Greenwich Mean Time) is currently 2h 30m behind IRT (Iran Standard Time). The exact difference can change when one or both zones transition into or out of daylight saving time.
Does IRT or GMT observe daylight saving time?+
IRT: does not observe daylight saving time. GMT: observes daylight saving time.
When is the best time to schedule a meeting between IRT and GMT?+
The strongest overlap is 12:00–16:00 IRT (09:30–13:30 GMT), giving 5 hours when both sides are within standard 9am-5pm working hours.
What time is it in London when it is 12:00 noon in Tehran?+
When it is 12:00 Wed in Tehran (IRT), it is 09:30 Wed in London (GMT).
Which IANA time zone identifiers are used for IRT and GMT?+
IRT maps to "Asia/Tehran" in the IANA database. GMT maps to "Europe/London". These identifiers are what most software libraries use to convert times accurately, including DST handling.
Is Tehran ahead of or behind London?+
Whether Tehran (IRT) is ahead of or behind London (GMT) depends on the current UTC offsets. Right now GMT is 2h 30m behind IRT. The live converter and side-by-side clocks above always reflect the current direction.
What are the current UTC offsets for IRT and GMT?+
IRT is UTC+03:30 (GMT+3:30) and GMT is UTC+01:00 (GMT+1). Both offsets shift by one hour when the corresponding region enters or exits daylight saving time, so the live values on this page are the source of truth.
Can I schedule meetings during business hours for both IRT and GMT?+
Yes. There are 5 hours of overlap during standard 9am-5pm working hours, with the strongest window at 12:00–16:00 IRT.