Why Does the Military Use 24 Hour Time? (Explained)

Written by

John Cotton


Logan Miller

why does the military use 24 hour time

Do you know why the military adopts the 24-hour clock? You might have seen that military personnel in movies and television programs talk about time differently than ordinary people do.

So, why does the military use 24 hour time?

Timing is crucial in military operations, and a consistent time system helps keep everyone on the same page. The 24-hour clock also helps with cross-unit and time-zone synchronization.

This article will explain how it started, how does military time work, why the military adopts it, and more.

Military Time Meaning

By definition, military time is a 24-hour clock used by the military for accurate time representation in all its schedules and urgent military operations. Military time is expressed as a number from 00 and 23 at each hour of the day.

For example, 1:00 PM is written as 1300 in military time. Hours are expressed by the first two numbers, and minutes by the last two digits.

Military Time Explained


1. History/origin

To understand where military time started, who invented it, and why the military uses 24-hour time, let’s travel back in time.

  1. It is in the year 2100 BC that time was believed to have originated. From stars aligning for 360 days to the constellations in the night sky — it was believed that Egyptians started the belief of how time will be counted for years to come.
  2. The Egyptians of the 11th dynasty used a coffin lid, known as the “Diagonal Star Table,” as evidence of time.
  3. In 147 to 127 BC, an astronomer, Hipparchus, came up with the idea of equinoctial hours.

Hipparchus observed the phenomenon of the consistent time of each season. There are exactly 60 minutes in an hour, and that hour remains constant throughout the day and night.

  1. In the eighth century, China used a water clock to serve as their 24-hour clock.
  2. In the year thirteenth century, Abū al-Ḥasan al-Marrakushi constructed the hour lines used in sundials. Then, his invention significantly enhanced time precision in sundials.
  3. Clocks were then developed later, and the standard 24-hour day became divided into 12-hour increments. The military, which puts importance on accuracy and precision, switched to the 24-hour clock.

2. Benefits/ Advantages of Military Time

  • Minimizes time zone discrepancies

Timekeeping during the day is easier because of military time. In addition, military time is ideal for travelers. It greatly helps with tracking time and converting different time zones around the world.

  • Better time management

The 24-hour time system is helpful in keeping track of time. It’s simple to make a day-to-day schedule.

Another thing, arranging meetings or calls for your company with members from different time zones is easier with the same 24-hour time system.

  • Easier time difference calculation

When dealing with time-sensitive events or activities, it helps prevent miscommunication.

An example: you book a schedule at 7:00 AM. Instead of coming to your appointment at 7:00 AM, you went in at 7:00 PM. This can possibly happen with the small mistake of one letter only.

It’s usually only a little inconvenience at most. But picture yourself in charge of a military operation, and you realize you made a mistake in calculating the time because you confused AM with PM.

A time that is not under military time standards might have serious consequences for your operation.

3. Who uses military time?

  • Pilots, air traffic control towers, and other aviation personnel adopt a 24 hour clock system. Securing everyone on time is important, therefore they employ military time.


After landing a plane, they can rely on reliable weather forecasts and other data, which is important for keeping everyone safe.


  • Government and local employees use military time to arrange schedules, meetings, and city events.
  • Hospitals use military time in many aspects. It helps with recording patients’ health information. Also, military time is used in healthcare to treat patients.

Outpatient clinics and hospitals that treat countless patients at once can better communicate their patients’ treatment using military time.

  • Astrologists, scientists, and meteorologists also use military time to stay organized. Meteorological radar, satellite imagery, maps, and charts all use a 24-hour timetable.

4. How do you say, read, and calculate military time?


  • How to read military time: In reading military time, you must learn to identify the four-digit numbers. Hours are stated as the first two numbers, minutes are by the last two digits.

Here are some examples of military time and how to say it:

12-Hour Clock 24-Hour Clock How To Say It
12:00 PM 1200 Twelve hundred hours
1:00 PM 1300 Thirteen hundred hours
2:00 PM 1400 Fourteen hundred hours
  • How to know the method to convert military time from standard time: The military time format does not include a colon.

The format is: In 24-hour time, 12:00 AM is written as 0000.

12:00 AM is written as 0000 hrs, while 12:00 PM is written as 1200 hrs. So, for example, you want to convert 3:00 PM standard time to military time.

Since 12:00 PM = 1200 hrs, then 3:00 PM is 1500 hours.

The minutes can also be added, just like on a standard 12-hour clock. For example, 3:27 pm is written as 1527 hours.

In addition, you can also use another military time converter available.

Frequently Asked Questions

Why was military time created?

The military adopted the 24-hours clock system as the world war advanced. US military time helps to avoid the confusion between the ordinary AM and PM hours.

What places use the 24-hour time system?

Many countries in Europe use military time systems. These countries include France, Germany, the United Kingdom, Romania, and more.

In southeast Asia, Vietnam has used a 24-hour clock ever since the 19th century.

Why is military time different from regular time?

Military time is different from the regular time in terms of its format. The military uses a 24-hour time system. In this format, the first two numbers indicate the hour, while the second pair indicates the minute.

Adding zeros is required in military time. For three o’clock, for instance, you would write 0300 instead of 6. The format uses a 12-hour time system and is written with a colon for regular time.

What do you mean by Zulu Time?

In the military time context, Zulu Time is referred to as Zero Merdian time zone or Greenwich Mean Time (GMT). It was developed to distinguish various time zones from one another.

Zulu Time is denoted as the letter Z which is added after the last number of the military time format—for example, 1200Z.


Finally, we’ve learned more details on “why does the military use 24 hour time”. For them, it guarantees accurate timekeeping.

It also simplifies communication and collaboration across time zones.

Not only the military uses military time. Different sectors such as aviation, healthcare, transportation, and the government, have adopted it.

If you are a citizen, learning to read military time sometimes seems complicated at first. Yet, military time vs standard time isn’t that different after you’ve gotten the hang of it.

Learning to read military and standard time can be an advantage wherever you go. So, enjoy learning it!

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