Most people use the traditional 12-hour clock, but some, including the military, use a different clock, a 24-hour military clock.

The idea of the 24-hour military time comes from the late-19th century adaptation of the German Midnight Starting System, but it may have been developed long before that.

It was said that Hipparchus. invented the 24-hour clock time as early as 147 B.C. “to propose dividing the day into 24 equinoctial hours based on the 12 hours of daylight and 12 hours of darkness observed on equinox days.”

In modern days, the 24-hour clock is affiliated with the American military, who officially adopted the 24-hour system in World War II on July 1, 1942. It makes sense since the military operates at all hours of the day and night. By using a 24-hour clock, they can avoid the confusion between a.m. and p.m. hours.

It isn’t just the military that uses the 24-hour time. It is also used by scientists, but most civilians in the United States use a 12-hour clock. “The 24-hour clock is primarily used in the non-English speaking countries in Europe, Latin America, Asia and Africa.” (Sourcetacticalgear.com)

The 24-hour clock is actually easy to understand. Since the 12 hour clock-time resets after 12 am, the 24-hour clock-time actually doesn’t reset at 12 am. It resets to 00:00 at midnight, so what many people would say is 2 pm, for example, is referred to as 1400 hours, since midnight to noon are the first twelve hours and the next twelve hours continues to add 12 to traditional time.

People should learn 24-hour military time because it is used in many contexts and helps avoid confusion between am and pm!