EST — Eastern Standard Time

Eastern Standard Time (EST) is the time zone used by the eastern portion of the United States and Canada during the winter months, running five hours behind Coordinated Universal Time. It covers major population centers including New York City, Washington D.C., Philadelphia, Atlanta, and Toronto, making it one of the most widely used time zones in North America. The zone spans from the Atlantic coast westward to portions of Indiana, Michigan, and the eastern edge of the Great Lakes region.

EST was formally established with the Standard Time Act of 1918, though railroads had already adopted standardized time zones in 1883 to replace the confusing patchwork of local solar times used by different cities. The Eastern time zone has long served as the reference point for American business and media, with the New York Stock Exchange, major television networks, and the federal government all operating on Eastern time.

During daylight saving time, which runs from the second Sunday in March to the first Sunday in November, clocks in the Eastern time zone are set forward one hour to Eastern Daylight Time (EDT, UTC-4). Not all areas within the zone observe DST; parts of Indiana historically resisted the change, though most of the state adopted it in 2006.