London to GMT
-1hLondon
BSTSOURCEGMT
GMTGreen rows indicate typical business hours (9 AM - 5 PM)
BST and GMT on the World Map
The map below highlights the BST (Greenwich Mean Time) and GMT (Greenwich Mean 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.
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 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.
Big Ben is actually the name of the bell inside the Elizabeth Tower, not the tower itself.
Time Conversion Guide: London to GMT
London runs on British Summer Time (BST) at UTC+01:00, currently observing daylight saving time. GMT runs on Greenwich Mean Time (GMT) at UTC+00:00. That puts London 1 hour behind GMT — a difference of -1h at the current offsets.
In practice, when it is 9:00 AM in London it is 8:00 AM in GMT. Midnight in London is 11:00 PM in GMT.London observes daylight saving time while GMT does not, so the gap narrows or widens by an hour part of the year.
London to GMT time conversion table
| London (BST) | GMT (GMT) | Day |
|---|---|---|
| 12:00 AM | 11:00 PM | previous day |
| 6:00 AM | 5:00 AM | same day |
| 7:00 AM | 6:00 AM | same day |
| 8:00 AM | 7:00 AM | same day |
| 9:00 AM | 8:00 AM | same day |
| 12:00 PM | 11:00 AM | same day |
| 3:00 PM | 2:00 PM | same day |
| 5:00 PM | 4:00 PM | same day |
| 6:00 PM | 5:00 PM | same day |
| 9:00 PM | 8:00 PM | same day |
Why people convert London to GMT time
- Scheduling a call from London to GMT: a 10:00 AM start in London lands at 9:00 AM in GMT, so you can confirm the slot without doing the arithmetic yourself.
- Finding shared working hours: both London and GMT are inside the 9-to-5 working day between 10:00 AM and 5:00 PM BST time (9:00 AM–4:00 PM GMT). That is roughly 7 hours of usable overlap.
- Watching a live event or market open: London viewers need 8:00 AM in GMT to catch a 9:00 AM start there, and 1:00 AM if the event is anchored to London.
- Always state the zone abbreviation, not just the hour. "3:00 PM BST" is unambiguous; "3 PM" across a -1h gap is not.
- Block 10:00 AM–5:00 PM BST as the recurring meeting window if you work primarily from London and need GMT colleagues present.
- London: Clocks fall back on Sun, Oct 25, 2026. Re-check this page after that date because the offset changes and so does the -1h gap.
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 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 London and GMT
Both London and GMT sit inside the 9 AM – 5 PM working day between 10:00 AM–5:00 PM BST, which is 9:00 AM–4:00 PM GMT. That gives roughly 7 hours of shared time — the safest window for a live call or meeting.
Business hours overlap
London and GMT share 7 hours of working-hours overlap (10:00 AM–5:00 PM BST), so scheduling a live meeting is straightforward.
London is 1 hour behind GMT (BST UTC+01:00 → GMT UTC+00:00). The shared working window is 10:00 AM–5:00 PM BST. Remember to re-check around daylight-saving transitions.
🕐 Daylight Saving Time Info
London
☀ Currently in DST
Standard: UTC+00:00 · DST: UTC+01:00
Clocks fall back on Sun, Oct 25, 2026
GMT
☀ 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 London and GMT?
London (BST, UTC+01:00) is 1 hour behind GMT (GMT, UTC+00:00). The gap is currently -1h.
How do I convert London time to GMT time?
Add -1h to London local time. For example, 9:00 AM in London is 8:00 AM in GMT.
What time is it in GMT right now?
GMT uses GMT at UTC+00:00. Use the live converter at the top of this page — it updates in real time and already accounts for the -1h offset from London.
What is the best time to call GMT from London?
Call between 10:00 AM and 5:00 PM BST — that maps to 9:00 AM–4:00 PM GMT and keeps both parties inside the working day.
Which is behind, London or GMT?
London is 1 hour behind GMT. When it is 12:00 PM in London it is 11:00 AM in GMT.
Do London and GMT use different time zones?
London (UK) uses BST at UTC+01:00, while GMT uses GMT at UTC+00:00. They actually share the same IANA zone.
Does daylight saving time affect the London–GMT difference?
Yes at the moment: London is on daylight saving time and GMT is not, so the -1h gap shifts by an hour when exactly one of them changes clocks.
Which other cities share London's time zone?
BST also covers London, Dublin, Lisbon, Accra, Reykjavik, Edinburgh, Casablanca, Dakar and 5 more.
Which countries use BST, London's zone?
BST is used in United Kingdom, Ireland, Iceland, Portugal (mainland), Ghana, Senegal, Mali, Mauritania and 7 more.
Is there a day difference between London and GMT?
Not normally. The -1h gap only pushes the date over the previous day.
What is the time difference between London and GMT?
GMT is -1h 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 GMT in?
GMT operates on its local timezone.
What are the business hours in London?
Standard business hours in London are 9:00 AM - 5:00 PM GMT.
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 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 London, what time is it in GMT?
When it is 12:00 AM (midnight) in London (GMT), it is -1h later in GMT (GMT).
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