Quick answer
New York and London share a 3-hour overlap in both winter and summer: 9 AM–12 PM EST/EDT = 2–5 PM GMT/BST. The 5-hour gap is maintained year-round because both cities observe DST simultaneously. The overlap expands to 4 hours only during the March and October transition windows (EDT vs GMT). The single best recurring slot is 9 AM Eastern in all seasons.
Overlap window: winter vs summer
| Season | New York | London | Overlap size |
|---|---|---|---|
| Winter (Nov–Mar) | EST (UTC‑5) | GMT (UTC+0) | 3 hours — 9 AM–12 PM / 2–5 PM |
| Summer (Apr–Oct) | EDT (UTC‑4) | BST (UTC+1) | 3 hours — 9 AM–12 PM / 2–5 PM |
| March transition (2 wks) | EDT (UTC‑4) | GMT (UTC+0) | 4 hours — 9 AM–1 PM / 1–5 PM |
| Oct transition (1 wk) | EDT (UTC‑4) | GMT (UTC+0) | 4 hours — 9 AM–1 PM / 1–5 PM |
Best meeting slots
- 9 AM EST / 2 PM GMT — the standard. Both sides at full working capacity. London has 3 hours to act on outcomes before 5 PM. See 9 AM EST in London.
- 10 AM EST / 3 PM GMT — comfortable for both. London has 2 hours of follow-up time. Good for longer sessions (60–90 minutes). See 10 AM EST in London.
- 11 AM EST / 4 PM GMT — tight for London. One hour before standard close. Reserve for short calls (30 minutes or less). See 11 AM EST in London.
- 8 AM EST / 1 PM GMT — early for New York but gives London a generous 4 hours after the call. Best when London needs significant follow-through time the same day. See 8 AM EST in London.
Who uses this route and how
Financial services — New York and London are the two largest financial centres in the world. The NYSE opens at 9:30 AM EST; the LSE opens at 8 AM GMT. The natural briefing slot is 9 AM EST / 2 PM GMT: New York arrives at the call after pre-market preparation; London is well into its trading day with four hours of context. This is the most institutionalised meeting time in global finance.
Technology and SaaS — US East Coast product or sales teams with London engineering or operations counterparts use 9 AM Eastern as the daily standup anchor. London starts the meeting having processed the morning's work; New York uses the sync to orient its own day. The structure is information-efficient: London reports, New York acts.
Consulting, legal, and professional services — Client calls at 9 or 10 AM Eastern give London clients 3–4 hours to process advice and take action the same day. A decision delivered to London at 2 PM has a materially different outcome than one delivered at 4 PM — the difference in available follow-up time is consequential for time-sensitive matters.
Media and advertising — US publishers, streaming platforms, and agencies with London offices use the 9–10 AM Eastern window for editorial briefings and campaign reviews. The mid-afternoon London time is productive for creative review work — past the post-lunch dip, before the end-of-day mental shift.
The March and October transition windows
The US moves to EDT on the second Sunday of March. The UK moves to BST on the last Sunday of March — typically 2–3 weeks later. During that window, New York is on EDT (UTC‑4) and London is still on GMT (UTC+0): a 4-hour gap instead of the usual 5. A 9 AM EDT call reaches London at 1 PM GMT — one hour earlier than the winter configuration. The overlap expands to 4 hours during this period.
The reverse occurs in late October. The UK reverts to GMT before the US reverts to EST, briefly creating the same 4-hour gap in the opposite seasonal context. Both windows are short (1–2 weeks) but affect recurring meetings that are not set to dynamic IANA timezones.
Fix: set calendar events to America/New_York for New York participants and Europe/London for London participants. Both IANA identifiers handle DST transitions automatically, so the displayed meeting time adjusts without manual intervention.
Practical scheduling rules for this route
- Book recurring meetings at 9 AM Eastern as the default — it is the slot with the most consensus and the best post-meeting follow-up window for London
- Write invites as "9:00 AM New York / 2:00 PM London" — city names, not timezone abbreviations
- Front-load agenda items requiring London action so they are resolved before the call passes the 30-minute mark
- If the meeting runs long (over 60 minutes), push past-the-agenda items to async rather than extending into London's final hour
- Review the London landing time each March and October — transition weeks shift it by one hour in each direction
Frequently asked questions
What are the overlapping business hours between New York and London?
In winter (EST/GMT), 3 hours: 9 AM–12 PM Eastern = 2–5 PM London. In summer (EDT/BST), 4 hours: 9 AM–1 PM Eastern = 1–5 PM London. The best single slot is 9 AM Eastern in both seasons.
What is the best meeting time for New York and London?
9 AM Eastern (EST in winter, EDT in summer). London receives the call at 2 PM GMT in winter or 2 PM BST in summer — mid-afternoon with 3 hours remaining before 5 PM. This is the standard for finance, technology, and professional services teams on this route.
Does the New York–London overlap change in summer?
Not significantly. Both cities observe DST together: New York moves to EDT (UTC‑4) and London moves to BST (UTC+1) simultaneously. The 5-hour gap is maintained and the overlap stays at 3 hours — 9 AM EDT = 2 PM BST, the same relationship as 9 AM EST = 2 PM GMT. The 4-hour overlap occurs only during the March transition window (EDT vs GMT). See the transition windows section for details.
What happens to New York–London meetings during the March DST transition?
The US moves to EDT 2–3 weeks before the UK moves to BST. During those weeks the gap is 4 hours (EDT vs GMT), not the usual 5. A 9 AM EDT call reaches London at 1 PM GMT — earlier than the winter configuration. Set calendar events to IANA timezones (America/New_York, Europe/London) to handle this automatically.