We've changed our name — alarm-clock.org is now timeandspace.science. Same tools, same pages, new address.
23:00 in 12-Hour Time
23:00 is 11:00 PM.
Written 2300 in military time and said “twenty-three hundred hours”. Going the other way, 11:00 PM is 23:00.
The 23:00 hour is the last hour of the day — 23:59 is the deadline every system means when it says 'end of day'.
24-hour clock
23:00
12-hour clock
11:00 PM
Said aloud: “twenty-three hundred hours” on the 24-hour clock, “eleven o'clock at night” on the 12-hour one.
Why 23:00 converts the way it does
This is the half of the day that actually changes. From 13:00 to 23:00, subtract 12 to get the 12-hour hour and label it PM: 23 − 12 = 11, so 23:xx is 11:xx PM. Going the other way, add 12 to any PM hour except 12 PM itself.
The minutes are the same on both clocks — a whole hour stays a whole hour — and 23:00 is at night, which is the information the AM/PM label is carrying.
Need this time to actually do something? Set an alarm for 11:00 PM, or use the timer to count a length of time instead of waiting for a clock time.
Common questions
What is 23:00 in 12-hour time?
23:00 is 11:00 PM. The minutes are unchanged; the hour is 23 − 12 = 11, and it takes PM.
What is 11:00 PM in 24-hour time?
11:00 PM is 23:00, written 2300 in military time.
How do you say 2300 out loud?
In military time it is said "twenty-three hundred hours". On a 12-hour clock the same moment is "eleven o'clock at night".