What Do AM and PM Mean? Definition, Examples, Facts.
Kids often get confused while determining the time of the day as AM and PM. It can be confusing that 12 A.M. indicates the middle of the night when we associate A.M. with morning time. An excellent way to remember this is that midnight is the start of the day, and even though it feels like the middle of the night to most people, the date changes and a new day begins at midnight. In the 12-hour clock system, the 24 hours of the day are divided into two intervals: am and pm. Each interval consists of 12 hours.
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Time: A.M. and P.M.
The image above shows the time referred to as AM vs PM. 12 at midnight is am, whereas 12 noon is pm. A day is made up of hours, minutes, and seconds. These units help us identify the time. There are 24 hours in a day, 60 minutes in an hour, and 60 seconds in a minute. If we want to say 10:20, 10 would be the hour, and 20 would be the minutes. There are two types of clock systems in the world. One is a 24-hour clock format, while the other is a 12-hour clock. A 12-hour clock represents the 24 hours of the day with the numbers 1-12, followed by AM or PM. The first 12-hour period, from midnight to noon, is AM. And the 12 hours from noon to midnight is P.M.
What do Am and Pm Stand For?
They are the Latin words used to refer to time. The meaning of AM and PM is ‘Ante Meridiem’ and ‘Post Meridiem’, which means before noon or midday. We associate P.M. with the afternoon and evening. P.M. is an abbreviated term for ‘Post Meridiem,’ which implies afternoon or after midday. In a 12-hour clock, these are used as time indications centered around noon. So, is AM morning or night and pm day or night? We can answer this by looking at some times; 10 AM is in the morning, and 2 PM is 2 hours after noon. So, AM and PM can represent daytime. 11 PM is one hour before midnight, and 1 AM is one hour after midnight. So, AM and PM can be nighttime.
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12-hour Clock
The 12-hour clock system has the numbers 1 to 12, followed by am and pm. This clock also represents all 24 hours of the day. The hour hand of the clock has to revolve two times to complete a day.
If we say 6 A.M. is early in the morning, 6 P.M. would be in the evening. If 2 A.M. is after midnight, then 2 P.M. is in the afternoon.
We can use any abbreviation, including am, a.m., AM, or A.M., to denote the ante meridiem. On the other hand, pm, p.m., PM, or P.M. is the abbreviation for post meridiem.
24-hour Clock
A 24-hour clock refers to the digital time where the time 00:00 represents the start of the new day. At 23:59, a 24-hour clock resets to 00:00. While using a 24-hour clock, the indications of am and pm are not used as the hours; 1-12 are not repeated.
For example, instead of quarter past 3 in the morning or 3:15 A.M., we can recognize the time as 03:15 in 24-hour clock format.
Convert 12-hour clock time to 24-hour clock
Look at the following cases to convert a 12-hour clock time to a 24-hour format.
Case I: For the first hour of the day (i.e., 12:00 A.M. to 12:59 A.M.)
Subtract 12 hours and remove A.M.
For example,
The 24-hour clock time for 12:00 A.M. is 00:00
The 24-hour clock time for 12:30 A.M. is 00:30
Case II: For times between 1:00 A.M. to 12:59 P.M.
The hours and minutes remain the same. Just remove the A.M./P.M. from the time.
For example,
The 24-hour clock time for 10:45 A.M. is 10:45
The 24-hour clock time for 12:10 P.M. is 12:10
Case III: For times between 1:00 P.M. to 11:59 P.M.
Add 12 hours and remove P.M. from the time.
For example,
The 24-hour clock time for 4:17 P.M. is 16:17
The 24-hour clock time for 11:55 P.M. is 23:55
Convert 24-hour clock time to 12-hour clock
Observe the following cases to convert a 24-hour clock time to a 12-hour format.
Case I: For the first hour of the day (i.e., 00:00 or midnight to 00:59)
Add 12 hours and A.M. to the time.
For example,
The 12-hour clock time for 00:30 is 12:30 A.M.
The 12-hour clock time for 00:45 is 12:45 A.M.
Case II: For times between 01:00 to 12:59
If the time is between 01:00 to 11:59, add A.M. to the time, and between 12:00 to 12:59, add P.M.
For example,
The 12-hour clock time for 07:55 is 7:55 A.M.
The 12-hour clock time for 12:35 is 12:35 P.M.
Case III: For times between 13:00 to 23:59
Subtract 12 hours and add P.M. to the time.
For example,
The 12-hour clock time for 17:25 is 5:25 P.M.
The 12-hour clock time for 20:35 is 8:35 P.M.
Solved Examples
Question 1: Samaira wakes up at 7:30 in the morning. What is her wake-up in the 12-hour clock format?
Solution:
Samaira wakes up at 7:30 in the morning.
7:30 in the morning is ‘7:30 A.M.’ in 12-hour clock format.
So, her wake-up time is 7:30 A.M.
Question 2: Convert 11:45 pm to 24-hour clock format.
Solution:
To convert 11:45 P.M. to 24-hour clock format, we add 12 hours and remove P.M.
So, 11:45 in a 24-hour format is 23:45.
Question 3: Write the time three hours after 15:25 in a 12-hour clock format.
Solution:
Three hours after 15:25 is 18:25.
To convert 18:25 to 12-hour clock format, we must subtract 12 hours and add P.M. to the time.So, 18:25 in 12-hour clock format is 6:25 P.M.
Practice Problems
AM and PM – Definition with Examples
Attend this quiz & Test your knowledge.
1
Sam goes to school at 7:30 in the morning. His brother, Tom, leaves for school one hour later. Which of the following shows Tom’s leaving time?
6:30 A.M.
8:30 A.M.
6:30 P.M.
8:30 P.M.
Correct
Incorrect
Correct answer is: 8:30 A.M.
Sam goes to school at 7:30 A.M. Tom leaves one hour later or at 8:30 A.M.
2
How will you represent 8:55 P.M. in a 24-hour format?
08:55
16:00
20:00
20:55
Correct
Incorrect
Correct answer is: 20:55
To convert 8:55 P.M. to 24-hour format, add 12 hours to the time and remove P.M. So, 8:55 P.M. in 24-hour format is 20:55.
3
Which of the following is 4 hours after 12:00 A.M.?
04:00
08:00
16:00
20:00
Correct
Incorrect
Correct answer is: 04:00
4 hours after 12:00 A.M. or 00:00 is 04:00.
Conclusion
The clock which follows the 12-hour clock format has to include terms like am and pm. In this article, we talked about the terms and what they mean. The 12-hour system helps divide the 24 hours of the day into two 12-hour sections, in simple words, AM and PM. You can also explore more interesting topics on SplashLearn.
Frequently Asked Questions
How can I tell if it is A.M. or P.M. from a 24-hour clock format?
From 00:00 to 11:59 (of a 24-hour clock), the time is represented as A.M. Between 12:00 and 23:59 (of a 24-hour clock), the time is represented as P.M. A.M. means Ante Meridiem and P.M. means Post Meridiem.
Do we capitalize the words AM and PM?
We can write the words A.M. and P.M. in both lowercase and uppercase.
What time is considered to be the start of the new day?
Most often, midnight is considered the start of a new day because it is associated with the hour 00:00.
When are AM and PM not used?
While using a 24-hour clock, the indications of A.M. and P.M. are not used as the hours 1-12 are not repeated.
