12-hour clock
12-hour clock: Time counting system
The 12-hour clock is a way of dividing the 24 hours of the day into two sections. The two halves are called ante meridiem (a.m.) and post meridiem (p.m.).
Both names are from Latin, and numbered from 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 and 12. Time from midnight to noon is a.m. and from noon to midnight p.m. The table at right shows how it relates to the 24-hour clock.
| 24-hour clock | 12-hour clock |
|---|---|
| 00:01 | 12:01 AM |
| 01:00 | 1:00 AM |
| 02:00 | 2:00 AM |
| 03:00 | 3:00 AM |
| 04:00 | 4:00 AM |
| 05:00 | 5:00 AM |
| 06:00 | 6:00 AM |
| 07:00 | 7:00 AM |
| 08:00 | 8:00 AM |
| 09:00 | 9:00 AM |
| 10:00 | 10:00 AM |
| 11:00 | 11:00 AM |
| 12:00 | 12:00 PM |
| 13:00 | 1:00 PM |
| 14:00 | 2:00 PM |
| 15:00 | 3:00 PM |
| 16:00 | 4:00 PM |
| 17:00 | 5:00 PM |
| 18:00 | 6:00 PM |
| 19:00 | 7:00 PM |
| 20:00 | 8:00 PM |
| 21:00 | 9:00 PM |
| 22:00 | 10:00 PM |
| 23:00 | 11:00 PM |
| 00:00 | 12:00 AM |