Time - AM/PM vs 24 Hour Clock
Showing the Time
There are two major ways to show the time: "AM/PM" or "24 Hour Clock".
With the 24 Hour Clock the time is shown as how many hours and minutes since midnight.
With AM/PM the day is split into the 12 Hours running from Midnight to Noon (the AM hours) and the other 12 Hours running from Noon to Midnight (the PM hours).
| AM | PM |
| Ante Meridian | Post Meridian |
When: | Midnight to Noon | Noon to Midnight |
24 Hour Clock: | 0:00 to 11:59 | 12:00 to 23:59 |
Converting AM/PM to 24 Hour Clock
For the first hour of the day (12 Midnight to 12:59 AM), subtract 12 Hours
Examples: 12 Midnight = 0:00, 12:35 AM = 0:35
From 1:00 AM to 12:59 PM, no change
Examples: 11:20 AM = 11:20, 12:30 PM = 12:30
From 1:00 PM to 11:59 PM, add 12 Hours
Examples: 4:45 PM = 16:45, 11:50 PM = 23:50 PM
Converting 24 Hour Clock to AM/PM
For the first hour of the day (0:00 to 0:59), add 12 Hours, make it "AM"
Examples: 0:10 = 12:10 AM, 0:40 = 12:40 AM
From 1:00 to 11:59, just make it "AM"
Examples: 1:15 = 1:15 AM, 11:25 = 11:25 AM
From 12:00 to 12:59, just make it "PM"
Examples: 12:10 = 12:10 PM, 12:55 = 12:55 PM
From 13:00 to 23:59, subtract 12 Hours, make it "PM"
Examples: 14:55 = 2:55 PM, 23:30 = 11:30 PM
Midnight and Noon
"12 AM" and "12 PM" can cause confusion, so we prefer "12 Midnight" and "12 Noon".
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