Key facts
London is 5 hours ahead of Eastern Standard Time (EST) in winter. In summer when the US observes EDT, London (BST) is 4 hours ahead. Unlike the PST-to-London relationship, the gap changes by one hour between seasons because the US and UK switch clocks on different schedules.
The working-hours overlap is 7 AM to 12 PM Eastern in winter (12 PM to 5 PM London) and 9 AM to 1 PM EDT in summer (1 PM to 5 PM BST). This is a much wider window than PST-to-London, giving New York and London teams up to 5 hours of shared availability.
Understanding the gap: EST, EDT, GMT, and BST
Eastern time observes two offsets through the year:
- EST 鈥?Eastern Standard Time (UTC-5): First Sunday of November to second Sunday of March
- EDT 鈥?Eastern Daylight Time (UTC-4): Second Sunday of March to first Sunday of November
London:
- GMT 鈥?Greenwich Mean Time (UTC+0): Last Sunday of October to last Sunday of March
- BST 鈥?British Summer Time (UTC+1): Last Sunday of March to last Sunday of October
In winter: EST (UTC-5) and GMT (UTC+0) 鈫?5-hour gap. In summer: EDT (UTC-4) and BST (UTC+1) 鈫?5-hour gap again... almost. Both shift by 1 hour, which cancels out 鈥?so the gap stays at 5 hours for most of the summer. But the US switches clocks about 2 weeks before the UK in spring, and the UK switches back about 1 week before the US in autumn. During those windows, the gap is temporarily 4 hours (spring) or 6 hours (autumn).
The practical rule: 5 hours most of the year; check the tool around late March and late October.
Best meeting hours 鈥?EST and London
Standard business hours overlap window in winter (EST/GMT):
7:00 AM 鈥?12:00 PM Eastern (EST)
= 12:00 PM 鈥?5:00 PM London (GMT) 路 5-hour window
In summer (EDT/BST), the useful window is slightly later from New York:
9:00 AM 鈥?1:00 PM Eastern (EDT)
= 1:00 PM 鈥?5:00 PM London (BST) 路 4-hour window
Recommended slots
- 8 AM EST / 1 PM GMT 鈥?early New York start; London gets a full afternoon
- 9 AM EST / 2 PM GMT 鈥?comfortable for both; the most used US-UK slot
- 10 AM EST / 3 PM GMT 鈥?later start; London still has time before close of day
- 11 AM EST / 4 PM GMT 鈥?later New York; London approaching end of day
Hour-by-hour EST to London conversion
Winter gap: 5 hours (EST/GMT). Summer gap: 4 hours (EDT/BST).
| EST / EDT | GMT (winter) | BST (summer) | Within UK hours? | Page |
|---|---|---|---|---|
| 7:00 AM | 12:00 PM | 11:00 AM | Yes | 7 AM EST |
| 8:00 AM | 1:00 PM | 12:00 PM | Yes 鈥?popular | 8 AM EST |
| 9:00 AM | 2:00 PM | 1:00 PM | Yes | 9 AM EST |
| 10:00 AM | 3:00 PM | 2:00 PM | Yes | 10 AM EST |
| 11:00 AM | 4:00 PM | 3:00 PM | Yes | 11 AM EST |
| 12:00 PM | 5:00 PM | 4:00 PM | End of day GMT | 12 PM EST |
| 1:00 PM | 6:00 PM | 5:00 PM | After GMT hours | 1 PM EST |
| 2:00 PM | 7:00 PM | 6:00 PM | No | 2 PM EST |
| 3:00 PM | 8:00 PM | 7:00 PM | No | 3 PM EST |
| 5:00 PM | 10:00 PM | 9:00 PM | No | 5 PM EST |
Common scheduling mistakes 鈥?EST and London
Assuming the gap is always 5 hours
In summer when the US observes EDT, the gap is 4 hours (EDT to BST). In winter with EST, it is 5 hours. In the brief transition windows in March and October, it briefly becomes 4 or 6 hours. Always check before scheduling around those dates.
Booking afternoon Eastern calls for London
In winter, any Eastern time after 12 PM is outside London business hours. In summer, after 1 PM EDT is past 5 PM BST. Afternoon New York calls cannot include London in standard working hours.
Using timezone abbreviations without dates
EST and EDT differ by one hour. An invite that says "3 PM EST" sent in summer may confuse recipients who are now on EDT. Always include the full date and both city times in every invite.
Not using the summer advantage
EDT narrows the gap from 5 to 4 hours, giving New York teams a wider late-morning window to reach London. Teams that lock in an "8 AM EST" recurring meeting may want to shift to "9 AM EDT" in summer for a more comfortable New York start time without losing the London slot.
Frequently asked questions
How many hours ahead is London from EST?
London is 5 hours ahead of Eastern Standard Time (EST) in winter. In summer when the US observes EDT, London BST is 4 hours ahead for most of the season, with brief transition-week exceptions.
What is 9 AM EST in London?
9 AM EST is 2 PM GMT in London in winter. During US summer (EDT), 9 AM EDT is 1 PM BST in London.
What EST times are after London business hours?
In winter (EST), any time after 12 PM falls outside London standard hours (5 PM GMT). In summer (EDT), the overlap extends to 1 PM EDT (5 PM BST). After those points, London participants are outside working hours.
Why does EST have a better London overlap than PST?
EST (UTC-5) is 3 hours ahead of PST (UTC-8). London is 5 hours ahead of EST compared to 8 hours ahead of PST. This gives Eastern-based teams a significantly wider and later overlap window 鈥?up to 5 hours in winter versus 3 hours from Pacific time.