London to Tehran
+2h 30mLondon
GMTSOURCETehran
IRSTGreen rows indicate typical business hours (9 AM - 5 PM)
GMT and IRST on the World Map
The map below highlights the GMT (Greenwich Mean Time) and IRST (Iran Standard Time) timezone regions across the globe.
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.
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.
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.
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.
Iran Standard Time (IRST) is one of few timezones with a 30-minute offset (UTC+3:30).
London to Tehran Time Difference – Complete Guide
London, UK operates on the Greenwich Mean Time (UTC+00:00). Tehran, Iran uses Iran Standard Time (UTC+03:30).
The time difference between London and Tehran is 150 minutes (+2h 30m). When it's noon in London, it's 02:30 PM in Tehran.
Why Convert London to Tehran Time?
Navigating the time gap between London and Tehran 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 Tehran.
Remember: Daylight Saving Time changes can affect the time difference between London and Tehran. Always double-check the current offset before scheduling important events.
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.
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.
Best Time to Call Between London and Tehran
If you want to reach someone in Tehran during standard business hours (9 AM – 5 PM IRST), the best time to call from London would be:
- Tehran 9:00 AM = London 06:30 AM
- Tehran 12:00 PM = London 09:30 AM
- Tehran 5:00 PM = London 02:30 PM
Business Hours Overlap
London and Tehran have a partial business hours overlap. The best window for meetings and calls is when both locations are in their working hours.
Ultimately, understanding the +2h 30m difference between London and Tehran empowers you to coordinate better. Whether for business or personal reasons, this tool ensures you're always on time.
🕐 Daylight Saving Time Info
London
☀ Currently in DST
Standard: UTC+00:00 · DST: UTC+01:00
Clocks fall back on Sun, Oct 25, 2026
Tehran
Does not observe DST
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 London and Tehran?
Tehran is +2h 30m from London.
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 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 are the business hours in London?
Standard business hours in London are 9:00 AM - 5:00 PM GMT.
What are the business hours in Tehran?
Standard business hours in Tehran are 8:00 AM - 4:00 PM IRST.
What is the best time to schedule a call between London and Tehran?
The best overlap for a call is when both cities are in business hours. London works 9:00 AM - 5:00 PM GMT and Tehran works 8:00 AM - 4:00 PM IRST (+2h 30m difference). Try scheduling during the overlapping window for maximum convenience.
What currencies are used in London and Tehran?
London uses GBP (£) while Tehran uses IRR (﷼). Check current exchange rates when planning travel or business between these cities.
How do London and Tehran compare in size?
London has a population of approximately 8.8 million (metro: 14.8 million), while Tehran has approximately 9.4 million (metro: 16.8 million).
What are the major landmarks in London and Tehran?
London is known for Big Ben, Tower Bridge, Buckingham Palace. Tehran is famous for Azadi Tower, Golestan Palace, Grand Bazaar.
Do London and Tehran have stock exchanges?
Yes. London has the LSE (London Stock Exchange) and Tehran has the TSE (Tehran Stock Exchange). The +2h 30m time difference affects trading hour overlaps between these exchanges.
Which countries use GMT (Greenwich Mean Time)?
GMT is used in United Kingdom, Ireland, Iceland, Portugal (mainland), Ghana, Senegal, and 9 more countries.
Does GMT observe daylight saving time?
Yes, GMT switches to BST during summer months.
What are some interesting facts about GMT?
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.
Which cities are in the IRST timezone?
Major cities in the IRST timezone include Tehran, Isfahan, Mashhad, Tabriz, Shiraz, Karaj.
What is the UTC offset for IRST?
Iran Standard Time (IRST) is at UTC+03:30. During daylight saving time, it shifts to IRDT.
What should I know about the IRST timezone?
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).
When is it midnight in London, what time is it in Tehran?
When it is 12:00 AM (midnight) in London (GMT), it is +2h 30m later in Tehran (IRST).
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