Tehran to London
-2h 30mTehran
IRSTSOURCELondon
GMTGreen rows indicate typical business hours (9 AM - 5 PM)
IRST and GMT on the World Map
The map below highlights the IRST (Iran Standard Time) and GMT (Greenwich Mean Time) timezone regions across the globe.
IRST – Iran Standard Time
UTC+03:30Iran Standard Time (IRST) is the time zone for Iran, 3 hours and 30 minutes ahead of UTC.
- •IRST is one of only a few time zones with a 30-minute offset.
- •Iran observes daylight saving time, switching to IRDT (UTC+04:30).
- •Tehran has a metropolitan population of over 16 million.
GMT – Greenwich Mean Time
UTC+00:00Greenwich Mean Time (GMT) is the mean solar time at the Royal Observatory in Greenwich, London. It is the same as UTC+00:00.
- •GMT is based on the Prime Meridian (0° longitude) passing through Greenwich, London.
- •The Royal Observatory in Greenwich has been the reference point for GMT since 1884.
- •GMT and UTC are often used interchangeably, but UTC is based on atomic clocks.
- •Iceland uses GMT year-round and never observes daylight saving time.
- •The UK switches from GMT to BST (British Summer Time) in late March each year.
About Tehran
WikipediaTehran operates on Iran Standard Time (IRST), UTC+3:30. Iran's unique half-hour offset makes Tehran time distinctive for regional business coordination.
The Iranian weekend is Thursday-Friday.
About London
WikipediaLondon, where Greenwich Mean Time (GMT) originates, is the world's leading financial center alongside New York. The city bridges European and American business hours.
London was the first city to have an underground railway, opening in 1863.
Time Conversion Guide: Tehran to London
Tehran, Iran operates on the Iran Standard Time (UTC+03:30). London, UK uses Greenwich Mean Time (UTC+00:00).
The time difference between Tehran and London is 150 minutes (+2h 30m). When it's noon in Tehran, it's 08:30 AM in London.
Why Convert Tehran to London Time?
Navigating the time gap between Tehran and London requires careful planning. With a difference of 2.5 hours, finding a suitable time for both locations is essential for effective collaboration. This tool simplifies the process, allowing you to instantly see the corresponding time in London.
Remember: Daylight Saving Time changes can affect the time difference between Tehran and London. Always double-check the current offset before scheduling important events.
About IRST (Iran Standard Time)
Iran Standard Time (IRST) is one of the few time zones with a 30-minute offset. Iran observes daylight saving time (IRDT, UTC+04:30) from late March to late September. Tehran, the capital, is one of the largest cities in the Middle East.
About GMT (Greenwich Mean Time)
Greenwich Mean Time (GMT) is the clock time at the Royal Observatory in Greenwich, London, which sits on the Prime Meridian (0° longitude). GMT serves as the reference point from which all other time zones are calculated. The United Kingdom uses GMT during winter months and switches to British Summer Time (BST, UTC+01:00) from late March to late October. Several West African nations use GMT year-round. GMT is often used interchangeably with UTC (Coordinated Universal Time), although technically they are different – UTC is based on atomic clocks while GMT is based on Earth's rotation.
Best Time to Call Between Tehran and London
If you want to reach someone in London during standard business hours (9 AM – 5 PM GMT), the best time to call from Tehran would be:
- London 9:00 AM = Tehran 12:30 PM
- London 12:00 PM = Tehran 03:30 PM
- London 5:00 PM = Tehran 08:30 PM
Business Hours Overlap
Tehran and London have a partial business hours overlap. The best window for meetings and calls is when both locations are in their working hours.
To wrap up, keeping track of the -2h 30m gap between Tehran and London is essential for seamless communication. Bookmark this converter to stay on top of your schedule.
🕐 Daylight Saving Time Info
Tehran
Does not observe DST
London
☀ Currently in DST
Standard: UTC+00:00 · DST: UTC+01:00
Clocks fall back on Sun, Oct 25, 2026
Learn More About Time
Dive deeper into the fascinating world of timekeeping, time zones, and how they shape our global society:
Frequently Asked Questions
What is the time difference between Tehran and London?
London is -2h 30m from Tehran.
What timezone is Tehran in?
Tehran operates on Iran Standard Time (IRST), UTC+3:30. Iran's unique half-hour offset makes Tehran time distinctive for regional business coordination.
What timezone is London in?
London, where Greenwich Mean Time (GMT) originates, is the world's leading financial center alongside New York. The city bridges European and American business hours.
What are the business hours in Tehran?
Standard business hours in Tehran are 8:00 AM - 4:00 PM IRST.
What are the business hours in London?
Standard business hours in London are 9:00 AM - 5:00 PM GMT.
What is the best time to schedule a call between Tehran and London?
The best overlap for a call is when both cities are in business hours. Tehran works 8:00 AM - 4:00 PM IRST and London works 9:00 AM - 5:00 PM GMT (-2h 30m difference). Try scheduling during the overlapping window for maximum convenience.
What currencies are used in Tehran and London?
Tehran uses IRR (﷼) while London uses GBP (£). Check current exchange rates when planning travel or business between these cities.
How do Tehran and London compare in size?
Tehran has a population of approximately 9.4 million (metro: 16.8 million), while London has approximately 8.8 million (metro: 14.8 million).
What are the major landmarks in Tehran and London?
Tehran is known for Azadi Tower, Golestan Palace, Grand Bazaar. London is famous for Big Ben, Tower Bridge, Buckingham Palace.
Do Tehran and London have stock exchanges?
Yes. Tehran has the TSE (Tehran Stock Exchange) and London has the LSE (London Stock Exchange). The -2h 30m time difference affects trading hour overlaps between these exchanges.
Which countries use IRST (Iran Standard Time)?
IRST is used in Iran.
Does IRST observe daylight saving time?
Yes, IRST switches to IRDT during summer months.
What are some interesting facts about IRST?
IRST is one of only a few time zones with a 30-minute offset. Iran observes daylight saving time, switching to IRDT (UTC+04:30).
Which cities are in the GMT timezone?
Major cities in the GMT timezone include London, Dublin, Lisbon, Accra, Reykjavik, Edinburgh, Casablanca, Dakar.
What is the UTC offset for GMT?
Greenwich Mean Time (GMT) is at UTC+00:00. During daylight saving time, it shifts to BST.
What should I know about the GMT timezone?
GMT is based on the Prime Meridian (0° longitude) passing through Greenwich, London. The Royal Observatory in Greenwich has been the reference point for GMT since 1884.
When is it midnight in Tehran, what time is it in London?
When it is 12:00 AM (midnight) in Tehran (IRST), it is -2h 30m later in London (GMT).
Related Developer Tools
Explore more tools that work great with timezone conversions for international teams: