Military time converter

What is a military time converter?

A military time converter is a tool that translates a time written in the 24-hour clock (military time) into the familiar 12-hour clock with AM and PM, and the other way around. Instead of starting over at 1 after noon, military time counts hours straight through from 00:00 at midnight to 23:59 just before the next midnight. This removes the ambiguity of “7 o’clock” — there is no question whether 19:00 means morning or evening.

A short history of the 24-hour clock

Counting the day in 24 hours is far older than the modern military. Ancient Egyptians already divided daylight and darkness into twelve parts each, and astronomers have used 24-hour notation for centuries. Navies and armies adopted the system because clear, unambiguous timekeeping prevents costly mistakes when coordinating movements. Today the 24-hour clock is the everyday standard across most of the world, while the United States, Canada, and a few other regions keep the 12-hour AM/PM clock for civilian use.

How does the calculator work?

Pick a conversion direction, type the hours and minutes, and (for the standard clock) choose AM or PM. The converter returns the equivalent time in the other format.

• Standard to military: hours run from 1 to 12 with an AM/PM marker; the result is HH:MM.
• Military to standard: hours run from 0 to 23; the result is h:MM AM/PM.

Formulas

Converting a 12-hour time (hours $h$, with an AM/PM marker) to 24-hour hours $H$:

$H = \begin{cases} 0 & h = 12,\ \text{AM} \\ h & 1 \le h \le 11,\ \text{AM} \\ 12 & h = 12,\ \text{PM} \\ h + 12 & 1 \le h \le 11,\ \text{PM} \end{cases}$

Converting a 24-hour hour $H$ back to a 12-hour hour $h$ with a period:

$h = \begin{cases} 12 & H = 0 \\ H & 1 \le H \le 12 \\ H - 12 & 13 \le H \le 23 \end{cases}$

The minutes never change between the two formats.

Worked examples

Example 1: Standard to military (evening)

Convert 6:45 PM to military time. Since it is PM and the hour is not 12, add 12 to the hour:

$6 + 12 = 18$

The minutes stay the same, so 6:45 PM is 18:45.

Example 2: Noon and midnight

These two times are the classic traps:

• 12:00 PM (noon) stays as 12:00 in military time.
• 12:00 AM (midnight) becomes 00:00 in military time.

Example 3: Military to standard

Convert 18:45 to standard time. Because the hour is greater than 12, subtract 12 and label it PM:

$18 - 12 = 6$

So 18:45 is 6:45 PM.

Quick reference table

Practical notes

• In speech, military time is often read without a colon: 08:00 is “zero eight hundred” and 13:30 is “thirteen thirty”.
• The two formats only differ in how hours are labeled; minutes and seconds are identical.
• The single biggest source of mistakes is the noon/midnight boundary — remember that midnight is 00:00, not 24:00, and noon is 12:00.

Related converters

If you work with time a lot, you may also like our time unit converter, the time difference calculator, and the add time calculator.

Frequently asked questions

What is 12:00 AM in military time?

12:00 AM is midnight, which is 00:00 in military time. The next day technically begins at this moment.

What is 12:00 PM in military time?

12:00 PM is noon, which stays as 12:00 in military time.

How do you convert PM hours to military time?

For any PM time except 12:00 PM, add 12 to the hour and keep the minutes. For example, 9:15 PM becomes 21:15.

Why does military time use four digits?

Writing hours and minutes as HH:MM (or HHMM) keeps every time exactly four digits long, which avoids confusion and makes times easy to read at a glance.

Is 24:00 a valid military time?

No. Military time runs from 00:00 to 23:59. The moment after 23:59 is 00:00 of the following day, not 24:00.