The 24-hour clock writes time from 00:00 to 23:59 without using AM or PM. 00:00 is midnight and 12:00 is noon. Instead of the day restarting at 1:00, it continues counting: 13:00, 14:00, 15:00, and so on until 23:59.
Hospitals, airlines, military, IT, and international businesses use this system because it eliminates confusion. There’s no guessing whether 8:00 means morning or evening, 08:00 is always morning, 20:00 is always evening. Your computer and smartphone use 24-hour time internally to prevent scheduling errors.
How to Read 24-Hour Time
Once you understand the pattern, reading 24-hour time becomes as easy as reading regular time. Let’s break it down by parts of the day:
Early Morning (00:00–00:59)
These are the quiet hours just after midnight. 00:30 means 30 minutes past midnight, most people are fast asleep!
Morning Hours (01:00–11:59)
These look almost identical to regular time. 07:00 is 7 AM, 09:15 is 9:15 AM. Easy, right?
Noon (12:00)
Just like regular time, 12:00 is noon—lunchtime!
Afternoon and Evening (13:00–23:59)
Here’s where it gets interesting. These numbers are bigger than 12, which tells you it’s afternoon or evening.
The Magic Trick: For any time from 13:00 onward, just subtract 12 to get the familiar PM time:
- 13:00 – 12 = 1:00 PM
- 18:30 – 12 = 6:30 PM (dinner time!)
- 23:15 – 12 = 11:15 PM (almost bedtime!)
Special Note About Midnight:
00:00 means the start of a brand new day. Sometimes you might see 24:00 on schedules, this marks the end of a day, but it’s the exact same moment as 00:00 of the next day. It’s like saying “the very last second of today.”
This 24 Hour Time Chart is a side by side look at 12-hour and 24-hour time format.
Converting Between 12-Hour and 24-Hour Time
Now that you can read 24-hour time, let’s learn how to convert between 12-Hour and 24-Hour Time. This skill will help you whether you’re reading a train schedule or setting up your phone.
From 12-Hour to 24-Hour:
Morning Times (1:00–11:59 AM):
Keep the same numbers, but add a zero in front if needed to make it two digits:
- 7:05 AM → 07:05
- 11:59 AM → 11:59
Noon:
12:00 PM stays 12:00 (this one’s easy to remember!)
Afternoon and Evening (1:00–11:59 PM):
Add 12 to the hour number:
- 2:45 PM → 2 + 12 = 14:45
- 9:07 PM → 9 + 12 = 21:07
Midnight:
12:00 AM becomes 00:00 (think of it as “zero o’clock”)