What Does AM And PM Stand For?

AM PM is a time convention that distinguishes between the two 12-hour daily periods.

  • "AM" stands for ante meridiem, which is Latin for "before midday,"
  • "PM" stands for post meridiem, meaning "after midday."

The AM PM system is commonly used in English-speaking countries to indicate morning and afternoon/evening times.

What does AM stand for?

AM stands for the period from midnight (12:00 AM) to just before noon (11:59 AM). It represents the morning hours.


What does PM stand for?

PM stands for the time period from noon (12:00 PM) to just before midnight (11:59 PM), representing the afternoon and evening hours.


AM PM Full Form

The full form of AM is "ante meridiem," and the full form of PM is "post meridiem." These terms are derived from Latin and have the following meanings:

  • AM: "ante meridiem" translates to "before midday" or "before noon." It refers to the time period from midnight to just before noon.
  • PM: "post meridiem" translates to "after midday" or "afternoon/evening." It represents the time period from noon to just before midnight.

The AM and PM designations are used to differentiate between the two 12-hour periods in a day. They are commonly used in English-speaking countries to indicate morning and afternoon/evening times.


How do you convert the AM PM clock to a 24-hour clock?

To convert a time from AM PM format to a 24-hour clock format:

  • For AM times, leave the hour unchanged.
  • For PM hours, compute (add) an additional 12 to the hour.
  • Keep the minutes and seconds the same.


AM Examples:

Time AMConversion to 24 hour clock
2:30 AM2:30
7:45 AM7:45
9:10 AM9:10
10:15 AM10:15
11:55 AM11:55

 


PM Examples:

Time PMConversion to 24-hour clock
1:30 PM13:30
4:45 PM16:45
6:10 PM18:10
8:15 PM20:15
11:30 PM23:30


How to convert a 24-hour clock to an AM-PM clock?

To convert a time from a 24-hour clock format to an AM PM format:

  • If the hour is 12 or greater, subtract 12 from the hour and add "PM."
  • If the hour is less than 12, simply add "AM."
  • Keep the minutes and seconds the same.


24-Hour Clock Examples:

24-hour clockConversion to AM-PM time
8:008:00 AM
0:1512:15 AM
9:309:30 AM
18:456:45 PM
23:1011:10 PM

Tip: Discover the 24 hour clock converter, to help you with the tricky time calculations.

 


What are the key differences between AM and PM?

AM refers to the morning hours (midnight to just before noon), while PM refers to the afternoon and evening hours (noon to just before midnight).

AM stands for "ante meridiem" (before midday), while PM stands for "post meridiem" (after midday).

The 24-hour clock does not differentiate between AM and PM; it uses a continuous counting system from 0 to 23.


What are the two 12-hour periods?

The two 12-hour periods are AM (morning hours) and PM (afternoon/evening hours). AM represents the time from midnight to just before noon, while PM represents the time from noon to just before midnight.


How to differentiate between Midnight and Noon: AM or PM?

  • Midnight is conventionally considered the start of a new day, so it is referred to as 12:00 AM
  • Noon, on the other hand, is the midday point and is referred to as 12:00 PM
  • However, to avoid confusion, using "12:00 noon" or "12:00 midnight" to explicitly indicate these times is recommended.


Where Is the 12-Hour format used?

The 12-hour clock format is commonly used in English-speaking locations across the globe, including the United States, Canada, the United Kingdom, Australia, and many others. It is widely used in everyday life, including personal schedules, transportation timetables, business hours, and social events.


What is the 12-hour clock?

The 12-hour clock is a timekeeping system that divides a day into two 12-hour periods. It uses AM (ante meridiem) for the morning hours and PM (post meridiem) for the afternoon and evening hours. The clock cycles from 1 to 12 twice a day, uniquely identifying each hour within its respective period.


What is the 24-hour clock?

Referred to as military time or the 24-hour time format, it is a timekeeping system that expresses time using a 24-hour cycle. It eliminates the need for AM and PM distinctions by representing hours from 0 to 23. For example, 1:00 PM is represented as 13:00 in the 24-hour clock.


What time is 11:59 PM?

When we refer to 11:59 PM, we mean one minute before midnight, which is the end of the day. It is still considered part of the PM period.


Is PM morning or night?

PM refers to the afternoon and evening hours. It is considered part of the nighttime period rather than the morning. AM represents the morning period.


How to convert AM PM to 24 hours?

To convert AM PM time to the 24-hour clock format:

  • If the time is in the AM period, leave the hour unchanged.
  • If the time is in the PM period, add 12 to the hour.
  • Keep the minutes and seconds the same.


Is Noon 12 AM or 12 PM?

Noon is 12:00 PM, representing the midday point when the sun is at its highest position in the sky.


Is 12 AM Midnight?

Yes, 12 AM represents midnight, the start of a new day.


What is 12:30 AM in 24-Hour format?

12:30 AM in the 24-hour format is represented as 00:30.


How many hours between 8AM til 4PM?

From 8AM to 4PM you have 8 hours.

There are two ways to calculate this hours difference:

Using AM-PM time format:

  • Step 1: Divide the counting by midday. After that, from 8:00 AM to 12:00 PM is 4 hours, and from 12:00 PM to 4:00 PM, you get another 4 hours.
  • Step 2: Sum up these two numbers.  4:00 + 4:00 is 8 hours.

Alternative answer using 24-hour time format: 

  • Step 1: Convert the numbers to military time: 4:00 PM means 16:00 in 24-time format.
  • Step 2: Deduct 16:00 - 8:00 = 8 hours.

Tip: 8 hours is a working day, from 8 am to 4 pm. However, the typical workday in a factory is 7.30 am to 4 pm, with an additional half-hour for an unpaid 30-minute lunch break.


How many hours is 8AM to 5PM?

There are 9 hours between 8AM and 5PM?


Who established the 12-hour clock format?

The 12-hour clock format has ancient origins and has evolved over time. Its establishment is attributed to various civilizations and cultures throughout history, including the Babylonians, Egyptians, and Romans. The modern usage of the 12-hour clock format developed over centuries of timekeeping practices.


Evolution of timekeeping - From the sun to clocks

The evolution of timekeeping spans thousands of years, starting with early civilizations observing the sun's and stars' motion. Sundials, water clocks, and mechanical clocks gradually emerged to measure time more accurately. The adoption of standardized time systems and the development of digital clocks further refined timekeeping practices.


Using AM and PM in daily life at work and home

AM and PM are widely used in daily life for scheduling and time management. They help distinguish between morning and afternoon/evening appointments, meetings, events, and other activities. They are used in various contexts, such as work schedules, school timetables, transportation schedules, and personal calendars.


Key takeaways about AM PM time

  • AM refers to the morning hours (before noon) in full form, 
  • PM refers to the afternoon and evening hours (afternoon).
  • Converting from AM PM to the 24-hour clock involves leaving AM hours unchanged and adding 12 to PM hours.
  • The 12-hour clock format is commonly used in English-speaking countries, while the 24-hour clock is more prevalent in military, scientific, and international contexts.
  • Noon is 12:00 PM, 
  • Midnight is 12:00 AM.
  • AM and PM are used in various aspects of daily life, including work schedules, appointments, transportation, and personal time management.