What is 1600 in military time?
1600 is 4:00 PM on the 12-hour clock, and 16:00 on the civilian 24-hour clock. It is spoken aloud as “sixteen hundred hours” — never “4 o'clock”, and never with a colon in the written form.
The hour is over 12, so subtract 12: 16 − 12 = 4, and the time is PM.
Written down it is four digits with no separator and no AM or PM: 1600. The first two digits are the hour, the last two are the minutes, and the minutes are ordinary minutes — 1645 would be 4:45 PM.
Where 1600 sits in the day
1600 is 16 hours into the day and 8 hours from the next midnight. In the watch system it falls in the first dog watch, the end of the standard duty day. The dog watches are deliberately short — two hours instead of four — so the rotation shifts each day and nobody is permanently stuck with the middle watch.
The hours either side
Three hours in each direction, since the value you are checking is usually next to the one you actually need.
Everything else on the 24-hour clock
The full chart lists every hour and half hour from 0000 to 2330 and prints on one page — that link jumps straight to the 1600 row. For a value that is not on a half hour, the military time converter takes anything you type in either direction, including 4:00 PM and 1600.
If what actually tripped you up was midnight versus noon rather than this hour, the 12 AM vs 12 PM explainer covers why the 12-hour clock cannot settle that question on its own.