New York runs on Eastern Time (EST/EDT). London runs on GMT/BST. The difference is almost always 5 hours — but shifts briefly to 4 or 6 hours twice a year.

The Standard Answer

Most of the year: London is 5 hours ahead of New York.

New York 9:00am = London 2:00pm. New York 12:00pm = London 5:00pm. New York 5:00pm = London 10:00pm.

When the Gap Changes

Early March (US moves forward, UK hasn't yet): London is only 4 hours ahead for about 2 weeks.

Early November (US moves back, UK hasn't yet): London is 6 hours ahead for about 1 week.

Best Overlap Window

2pm–6pm London time = 9am–1pm New York time. This is the prime London–New York meeting window and works year-round.

New York vs London: Key Facts

New York uses EST (UTC−5) in winter and EDT (UTC−4) in summer. London uses GMT (UTC+0) in winter and BST (UTC+1) in summer. The typical difference is 5 hours, with New York 5 hours behind London.