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).

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".