London Time Zone — GMT vs BST, and Converting to US and Global Times
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London operates on two time zones across the year: Greenwich Mean Time (GMT, UTC+0) from late October to late March, and British Summer Time (BST, UTC+1) from late March to late October. Understanding which one applies — and whether the US has changed its clocks on a different schedule — determines the exact hour gap between London and your city.
The free time zone converter handles London time correctly by using the full IANA time zone database. Select "London (GMT/BST)" and it shows the accurate current UK time, not a fixed UTC+0.
London to US East Coast Conversions
| London Time | US Eastern (Winter) | US Eastern (Summer) |
|---|---|---|
| 9 AM GMT/BST | 4 AM EST | 4 AM or 5 AM EDT |
| 12 PM GMT/BST | 7 AM EST | 7 AM or 8 AM EDT |
| 2 PM GMT/BST | 9 AM EST | 9 AM or 10 AM EDT |
| 5 PM GMT/BST | 12 PM EST | 12 PM or 1 PM EDT |
| 6 PM GMT/BST | 1 PM EST | 1 PM or 2 PM EDT |
The "or" in the summer column reflects the 1–2 week transition windows when the US and UK change clocks on different dates, causing the gap to briefly be 4 hours instead of 5.
Sell Custom Apparel — We Handle Printing & Free ShippingThe US-UK DST Transition Window (When the Gap Changes)
Most of the year, London is either 5 hours ahead of Eastern (winter) or 5 hours ahead of Eastern (summer) — wait, that is the same number. Here is why:
In winter: London is on GMT (UTC+0), Eastern is on EST (UTC-5) → 5-hour gap. In summer: London is on BST (UTC+1), Eastern is on EDT (UTC-4) → still a 5-hour gap. Both sides move by 1 hour together.
The gap becomes 4 hours briefly during the spring and fall transition windows when one side has changed clocks and the other has not. In spring: the US moves its clocks about 2 weeks before the UK. For those 2 weeks, Eastern is on EDT (UTC-4) while London is still on GMT (UTC+0) — only a 4-hour gap. The same happens in fall: the UK falls back before the US, making the gap 4 hours for about a week.
If you have a recurring weekly call, be aware that it may appear at a different clock time during these 2-week windows. The timezone converter shows the live correct conversion for today's date.
London vs Paris, Berlin, Amsterdam (CET)
London and the rest of Western Europe (France, Germany, Netherlands, Spain) both observe summer time, but London is always 1 hour behind Central European Time (CET/CEST). London at 9 AM is Paris at 10 AM — year-round. This 1-hour offset is consistent because both regions spring forward and fall back on the same last Sunday of March and October.
For scheduling, treat London as 1 hour behind Paris/Berlin and 2 hours behind Eastern European capitals (Bucharest, Athens, Helsinki).
Convert London Time to US and Global Zones
Enter any London time — the converter knows whether today is GMT or BST and gives the correct conversion automatically.
Open Time Zone ConverterFrequently Asked Questions
How many hours is London ahead of New York?
Usually 5 hours. London is ahead by 5 hours year-round, except for a brief 1–2 week window each spring and fall when the US and UK clock changes do not align, briefly making it 4 hours.
Is London on GMT or BST right now?
London uses BST (UTC+1) from the last Sunday in March to the last Sunday in October, and GMT (UTC+0) for the rest of the year. The timezone converter shows the current correct London time automatically.
What is 9 AM London time in Eastern?
Normally 4 AM Eastern (London is 5 hours ahead). During brief DST transition windows, it may be 5 AM Eastern. Use the converter for today's exact answer.