What Is Military Time?

Military time, the 24 hour clock
(U.S. Air Force/2nd Lt. David J. Murphy)

Military time is a 24-hour clock designed to avoid confusion between daytime and nighttime hours, since the armed forces are in operation around the clock.

Also called the "24-clock," the system is commonly used in industries and professions in the United States and other parts of the world in which 24-hour operations are routine, including law enforcement, fire departments, hospitals, airlines and railroads.

How to Read Military Time

There is no a.m. or p.m. in military time, as numbers are not reused, but instead, each hour has its own number.

Any given time of day is expressed in four digits. The day in military time begins at midnight with 0000, pronounced "zero hundred hours" or simply "zero hundred."

You then add one hundred for each hour, so 1 a.m. is 0100 (zero one hundred) hours, 2 a.m. is 0200 (zero two hundred) hours and so forth.

In the four-digit expression of time, no colon separates the hours and minutes. For example, 6:30 a.m. in civilian time is written simply as 0630 in military time.

The morning hours are simple enough to understand. This ease continues through midday, which is 1200 (twelve hundred) hours.

Read More: Making Sense of Military Time

The military references to the afternoon and evening hours often take new enlistees in basic training longer to learn by heart.

After noon, instead of starting over with 1, military time continues chronologically, so that 1 p.m. is 1300 hours, 2 p.m. is 1400 hours and so forth.

The day ends just before midnight at what civilians would call 11:59 p.m., but which in military time is 23:59, or twenty-three fifty-nine hours.

For those still learning the 24-clock system, a simple way to translate afternoon and evening hours into civilian time is to subtract 12. For example, for 2000 hours, subtract 12 from 20 to get 8 p.m.

Read More: Military Lingo for New Military Spouses

Military Time Chart

12-Hour Clock

24-Hour Military Time

How to Say Military Time

12 midnight 0000 Zero hundred (hours)
1 a.m. 0100 Zero one hundred (hours)
2 a.m. 0200 Zero two hundred (hours)
3 a.m. 0300 Zero three hundred (hours)
4 a.m. 0400 Zero four hundred (hours)
5 a.m. 0500 Zero five hundred (hours)
6 a.m. 0600 Zero six hundred (hours)
7 a.m. 0700 Zero seven hundred (hours)
8 a.m. 0800 Zero eight hundred (hours)
9 a.m. 0900 Zero nine hundred (hours)
10 a.m. 1000 Ten hundred (hours)
11 a.m. 1100 Eleven hundred (hours)
12 noon 1200 Twelve hundred (hours)
1 p.m. 1300 Thirteen hundred (hours)
2 p.m. 1400 Fourteen hundred (hours)
3 p.m. 1500 Fifteen hundred (hours)
4 p.m. 1600 Sixteen hundred (hours)
5 p.m. 1700 Seventeen hundred (hours)
6 p.m. 1800 Eighteen hundred (hours)
7 p.m. 1900 Nineteen hundred (hours)
8 p.m. 2000 Twenty hundred (hours)
9 p.m. 2100 Twenty-one hundred (hours)
10 p.m. 2200 Twenty-two hundred (hours)
11 p.m. 2300 Twenty-three hundred (hours)

Why Does the Military Use 24-Hour Time?

One of the main advantages of using military time is eliminating ambiguity. Military routines and operations demand precision, and the use of the 24-clock system prevents any confusion over a.m. versus p.m.

"Precise time is crucial to navigation, geographical positioning for locating forces and targets, and secure communications," according to the Encyclopedia of Military Science. "Military time, therefore, is more than a method for counting the hours. It's also an authoritative source of time and a set of methods to disseminate synchronized time worldwide."

Although the phrase "military time" is commonly used, this time system was not invented by the military. The 24-hour clock had already been employed throughout Europe for years before the U.S. military adopted it.

The U.S. Navy began using the 24-hour clock in 1920, after becoming familiar with it during World War I.

The U.S. Army didn't officially adopt military time until 1942.

Read More: The Military Alphabet


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