Add five hours, or four — the date decides
Converting Eastern to UTC means adding the offset back on. In winter Eastern is UTC−5, so you add five hours. During daylight saving it is UTC−4, so you add four. Getting this backwards, or applying one rule year-round, is the most common timestamp bug in American systems.
Why you should store UTC in the first place
A wall-clock time with no zone attached is ambiguous, and one with a zone abbreviation attached is only slightly better. Storing the UTC instant removes the question entirely: it is a single point on the timeline that every system can render in local terms. Convert at the edges, when you display a value to a person, and keep the middle of your system in UTC.
Evening Eastern times land on the next UTC day
Anything from 7:00 PM Eastern in winter, or 8:00 PM in summer, is already tomorrow in UTC. A 9:00 PM Eastern event on a Monday is recorded as Tuesday in UTC, which is why a log search bounded by calendar date can miss the very events you are looking for.
Writing a time that survives being forwarded
The safest format pairs the local time with its UTC equivalent: “Thu 3 Sep, 10:00 AM New York (14:00 UTC)”. Anyone reading it can act on it without knowing whether daylight saving is in force, and it stays correct when the message is quoted three weeks later.