1. Introduction To The 24-Hour Clock
Military Time

2. Military Time
The military services were the first to use a 24-hour clock.
Always expressed in four digits with no colons used to separate hours and minutes.
Always use a O to complete the four-digit number-0300 instead of 300 (am hours)

3. State the time in hundreds – zero three hundred hours is 3:00 AM, twenty-two hundred hours is 10:00 PM
The 24 hour clock eliminates confusion between AM and PM hours.
AM – 0100 to 1200
PM – 1201 to 2400

4. To determine how 5:00 P.M. is expressed in military time, add 1200 and 0500 = 1700 hours
To determine how 12 midnight is expressed in military time, add 1200 and 1200 = 2400 hours.
Note: Midnight may also be written as is the highest number used because there is only 24 hours in a day.

5. Other ways to figure military time exist but beware different methods may have exceptions.
Example: 12 pm (noon) is written as 1200.
12 am (midnight) is written as 2400 or 0000.

6. Hours are numbered from 0-24. No need to use a. m. or p. m
Hours are numbered from No need to use a.m. or p.m. designations. For example:
1 am = 0100
3:30 am = 0330
10 am = 1000

7. 12 noon = 1200
2:30 pm = 1430
8 pm = 2000
10:15 pm = 2215
12 MN = 2400

8. Greenwich Time Standard time on a 12 hour clock
Includes colon ex: 1:00
Includes am or pm
More commonly used by non-military/medical personnel.