EST to GMT Converter

Here EST means Eastern Time, EST (UTC−5) in its winter and EDT (UTC−4) in its summer, as kept in New York; GMT means Greenwich Mean Time, fixed at UTC+0 (the UK itself moves to BST, UTC+1, in summer). So GMT is 5 h ahead of EST in January and 4 h ahead in July. Two 9-to-5 working days overlap by 3 h in January and 4 h in July.

People often search EST to GMT when they really want New York to London, and the two are not quite the same thing. GMT is a fixed clock, UTC+0, all year. London only uses GMT in winter; from the last Sunday in March to the last Sunday in October the UK is on British Summer Time (BST, UTC+1). This page converts to GMT itself, the fixed one, so in July 9:00 am in New York (EDT) is 1:00 pm GMT, but 2:00 pm on a London wall clock.

For New York to London the usual gap is five hours in both summer and winter, because both cities move their clocks. It drops to four hours for a few weeks a year: from the US change on the second Sunday in March until the UK change at the end of March, and again for the week between the UK falling back in late October and the US falling back in early November. Transatlantic meetings set in one city’s time drift by an hour on the other side during those weeks.

Rule of thumb: Add five hours to Eastern Standard Time, or four to Eastern Daylight Time, to get GMT; for a London wall clock in summer, add one more.