The time difference between UTC and Eastern Standard Time is 5 hours. EST is written as UTC−05:00, meaning clocks in the Eastern Time Zone show five hours earlier than UTC during standard time.
Eastern Standard Time is used during the colder part of the year in much of the eastern United States and parts of Canada. The same region generally switches to Eastern Daylight Time, or EDT, during daylight-saving time; EDT is only four hours behind UTC.
A common mix-up is confusing EST with the broader Eastern Time Zone. “Eastern Time” can mean either EST or EDT, depending on the date. For example, when it is 12:00 UTC, it is 7:00 a.m. EST, but 8:00 a.m. EDT.
The offset is based on the 75th meridian west of Greenwich. Similar UTC−05:00 offsets are also used year-round in places such as Colombia, Peru and Panama.