AM Full Form

AM Full Form: The full form of AM has been derived from the Latin word ‘Anti Meridiem’, which means ‘before midday. It is used in the 12-hour clock system to represent Before Noon and After Noon, respectively. They are also represented as ‘A.M.’ or ‘am’ and ‘P.M.’ or ‘pm.’

AM Full Form

This article contains the full form of AM and highlights the basics of the topic. 

The 12-hour clock is a system in which the 24 hours of the day are divided into two time zones: a.m. and p.m. (from the Latin term ‘post meridian, which means past midday). Each period consists of 12 hours designated by numerical digits: 12 (as zero), 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, and 11. The cycle of the 24-hour day starts at 12 midnight, runs through 12 noon, and continues to midnight at the end of the day. 

For example, if someone specifies a time by the clock at 7 O’clock, it’s a bit confusing to understand whether it’s 7 a.m. or 7 o’clock in the evening. 7 am is early in the morning, and 7 pm is late in the afternoon; 1 am is one hour after midnight, while 11 pm is one hour before midnight. Hence to remove this confusion, AM, and PM are used.

Midnight Confusion

Sometimes confusion arises in the 12-hour system when only a date and 12:00 am (midnight) are provided.

For example, suppose someone asks to pick set a birthday reminder at 12:00 am on September 13. In that case, it is not clearly understood whether to set a reminder at midnight between September 12 and September 13 or 24 hours later.

To overcome this confusion, 12:01 am could be used to indicate midnight of September 13 and 11:59 pm could be used to indicate the late night of September 12.

Converting 12-Hour to 24-Hour Format

A 24-hour clock, often referred to as military time, indicates the time according to the number of hours that have passed since midnight. For example, at 21:00, 21 hours have passed since the beginning of the current day.

To convert am or pm time to the 24-hour format, these rules are applied:

From midnight to 12:59 am, subtract 12 hours.

12:49 am = 0:49 (12:49 – 12)

From 1:00 am to noon, do nothing.

11:49 am = 11:49

From 12:01 pm to 12:59 pm, do nothing.

12:49 pm = 12:49

From 1:00 pm to midnight, add 12 hours.

1:49 pm = 13:49 (1:49 + 12)

Majority of the countries around the world use the 24-hour system. However, the 12-hour format, including am and pm, is officially used in several countries, including the United States, Canada (except Québec), Australia, New Zealand, and the Philippines.


AM Full Form is Anti Meridiem. It has been derived from the Latin word ‘Anti Meridiem’, which means ‘before midday. Here we have explained the full form of AM in detail.

People Also Reading:

Leave a comment