The UTC offset
is the time offset from Coordinated Universal Time
(UTC). It is mostly given as hour or hour and minute. Many time zones
employ two time offsets, one for standard time
and one for daylight saving time
. Before the introduction of UTC on 1 January 1972 Greenwich Mean Time (also known as Zulu time) was the same as Universal Time (UT).
Converting between time zones
UTC time to UTC+offset time
To convert from UTC to UTC+offset time zones, one adds the offset to the UTC time to get the UTC+offset time. The offset should be taken with the proper sign, so that it can be either a positive or a negative number. An example will illustrate.
Take the 00
time zone. Its offset is -5 hours, which means that one must add -5 hours to the UTC time to get the UTC-05:00 time (meaning, one must subtract 5 hours from the UTC time). For example, suppose that right now, the local time in the UTC time zone is 4:00 p.m. (16:00 military time
). What is then the local time right now in the UTC-05:00 time zone? The answer: it is 4:00 p.m. + offset = 4:00 p.m. + (-5 hours) = 4:00 p.m. - 5 hours = 11:00 a.m. (in military time: 16:00 + (-05:00) = 16:00 - 05:00 = 11:00).
At the same moment, the local time in the 00
time zone is 4:00 p.m. + offset = 4:00 p.m. + (5 hours) = 9:00 p.m. (in military time: 16:00 + (+05:00)= 21:00).
UTC+offset time to UTC time
In this case one must subtract
the offset from the UTC+offset, being careful to realize that subtracting a negative number means adding... Read More