24-hour clock Wikipedia

To effectively convert military time, you'll have to be familiar with the military time chart, military time zones, reading, and "speaking" military time. It spans across timezones, cities, states, languages, and in times of crisis, it can save your life. A large portion of the world uses military time for timekeeping. However, nations such as the US and the UK are more used to the 12-hour cycle, with only certain professionals relying on military time in the course of their duties. Despite its limited use in some countries, military time is a good timekeeping system for you to know as you’re likely to encounter it at some point in your life. For example, you could be forced to use military time while dealing with a first responder or traveling to a nation where the 24-hour clock is in standard use. To convert civilian time to military time, simply add 12 to numbers after noon. The question sometimes arises whether midnight is written as 2400 or 0000. Military and emergency services personnel refer to midnight both ways. However, digital watches and clocks that display time in a 24-hour format and computer equipment treat midnight as the start of a new day and express it as 0000. You can convert military time to civilian time for numbers after noon by subtracting 12 from the number.