Full Form of A.M and P.M
First of all, A.M. and P.M. both are the Latin abbreviations.
What is the A.M. and P.M. full form?
The Full form of A.M. is Anti Meridiem, used in 12-hour clock system to represent Before Noon.
The Full form of P.M. is Post Meridiem, used in 12-hour clock system to represent After Noon.
A.M. and P.M. (long form of A.M. and P.M.) are used to differentiate the day time and night time in the 12-hour time zone. 24 hours of a day are divided into two segments lasting 12 hours each. The first 12-hour duration runs from midnight to noon and is referred by A.M. The second 12-hour duration runs from noon to midnight and referred by P.M.
For Example:
If I say that I will come at 7 O’clock so it may be confusing for anyone that it is 7 O’clock in the morning or 7 O’clock in the evening. Thus, to differentiate this, AM and PM are used in 12-hour clock system.
Terminology of P.M. A.M. full form
- The term meridiem means “Midday”
- Ante means Before
- Post means After
- The term Ante Meridiem – AM means “before midday”
and
- Post Meridiem – PM means “after midday“
PM: It represents the time from noon to just before midnight. (12 PM to 11:59 PM)
AM: It represents the time from midnight to noon. (12:00 AM to 11:59 AM).
Convert AM PM Clock to a 24-Hour Clock
| 12-Hour Clock Time | Conversion to 24-Hour Clock | Tips for Conversion |
| 12:00 AM | 00:00 | Subtract 12 hours from the time for midnight (12 AM) to 12:59 AM. |
| 12:30 AM | 00:30 | Midnight to 12:59 AM subtracts 12 hours. |
| 10:00 AM | 10:00 | Hours between 1:00 AM and 11:59 AM remain the same. |
| 3:17 PM | 15:17 | Add 12 hours for times from 1:00 PM to 11:59 PM. |
| 11:49 PM | 23:49 | Add 12 hours for post-noon times. |
| 10:00 PM | 22:00 | Simply add 12 hours for times between 1:00 PM and 11:59 PM. |
In this table, times in the 12-hour clock are converted to the 24-hour clock using the guidelines:
- For AM times from 12:00 AM to 12:59 AM, subtract 12.
- For times between 1:00 AM and 11:59 AM, the time remains the same.
- For PM times between 1:00 PM and 11:59 PM, add 12 hours to convert.
Convert a 24-Hour Clock to AM-PM Clock
| 24-Hour Clock Time | Conversion to AM-PM Clock | Tips for Conversion |
| 0:40 | 12:40 AM | For times between 00:00 (midnight) and 0:59, add 12 and use AM. |
| 1:55 | 1:55 AM | From 1:00 to 11:59, simply attach AM to the time. |
| 3:45 | 3:45 AM | Times from 1:00 AM to 11:59 AM remain the same with AM attached. |
| 16:55 | 4:55 PM | Subtract 12 hours and add PM for times between 13:00 and 23:59. |
| 21:45 | 8:45 PM | Subtract 12 hours and attach PM for times after 12:59 PM. |
| 13:00 | 1:00 PM | For times from 13:00 to 23:59, subtract 12 and add PM. |
In this table, times in the 24-hour clock are converted to the 12-hour AM-PM clock using the following guidelines:
- For times between 0:00 (midnight) and 0:59, add 12 and use AM.
- From 1:00 to 11:59, simply attach AM.
- For times between 13:00 and 23:59, subtract 12 and add PM.
Conclusion
In conclusion, understanding the full form of AM and PM is essential for effective timekeeping. AM full form stands for Anti Meridiem, representing the hours before noon, while PM full form stands for Post Meridiem, representing the hours after noon. The use of AM and PM in the 12-hour clock system helps differentiate between daytime and nighttime hours.
To convert AM PM clock to a 24-hour clock, simple guidelines can be followed, such as subtracting 12 hours for midnight to 12:59 AM and adding 12 hours for 1:00 PM to 11:59 PM. Conversely, converting a 24-hour clock to AM-PM clock involves adding 12 hours for times between 00:00 and 0:59 and subtracting 12 hours for times between 13:00 and 23:59. Mastering these conversions ensures accurate timekeeping and avoids confusion between AM and PM.