Eastern Time (ET) is generally GMT-5 during Standard Time (EST) and GMT-4 during Daylight Saving Time (EDT).
Here's a more detailed explanation:
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Eastern Standard Time (EST): When Eastern Time observes standard time, it is 5 hours behind Greenwich Mean Time (GMT). So, EST = GMT-5.
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Eastern Daylight Time (EDT): During Daylight Saving Time, which typically runs from the second Sunday in March to the first Sunday in November, Eastern Time observes daylight time. At this time, it is 4 hours behind GMT. So, EDT = GMT-4.
To illustrate:
| Time Zone | Abbreviation | Offset from GMT | Period |
|---|---|---|---|
| Eastern Standard Time | EST | GMT-5 | Typically from November to March |
| Eastern Daylight Time | EDT | GMT-4 | Typically from March to November |
Therefore, to accurately determine the GMT equivalent of Eastern Time, you need to know whether Eastern Time is currently observing standard time (EST) or daylight saving time (EDT).
