Clocks
24-Hour Time vs 12-Hour Time: How to Read and Convert Military Time
October 22, 2026
You book a flight and it leaves at 17:45. Your train ticket
says 06:10. A colleague abroad suggests a call at 14:00. If you grew up with am
and pm, there's always that little pause while you work out what time it
actually is.
The good news is that 24-hour time is easier than it looks.
Once it clicks, a lot of people end up preferring it.
How 24-hour time works
The 24-hour clock counts the hours of the day from 0 to 23
instead of going 1 to 12 twice.
The day starts at 00:00, which is midnight. The morning runs
exactly like the 12-hour clock: 01:00 is 1 am, 09:30 is 9:30 am, and so on.
12:00 is noon.
After noon, instead of starting again at 1, the hours keep
counting: 13:00, 14:00, all the way to 23:59. Then it rolls back over to 00:00
and a new day starts.
No am, no pm, and no way to confuse morning with evening.
The easy way to convert
From 24-hour to 12-hour:
- If the
hour is 1 to 11, it's the same number, am.
- If the
hour is 12, it's 12 pm (noon).
- If the
hour is 13 or more, subtract 12 and add pm. So 17:45 is 5:45 pm, and 21:10
is 9:10 pm.
- If the
hour is 00, it's 12 am (midnight). So 00:30 is 12:30 am.
From 12-hour to 24-hour, just do the opposite. For pm times
after 12 pm, add 12. 3 pm becomes 15:00, 8:20 pm becomes 20:20. For 12 am,
write 00.
That's honestly all there is to it. After a week of
practice, you'll stop doing the maths and just recognize 18:00 as six in the
evening.
Quick conversion table
|
12-hour |
24-hour |
12-hour |
24-hour |
|
12 am (midnight) |
00:00 |
12 pm (noon) |
12:00 |
|
1 am |
01:00 |
1 pm |
13:00 |
|
2 am |
02:00 |
2 pm |
14:00 |
|
3 am |
03:00 |
3 pm |
15:00 |
|
4 am |
04:00 |
4 pm |
16:00 |
|
5 am |
05:00 |
5 pm |
17:00 |
|
6 am |
06:00 |
6 pm |
18:00 |
|
7 am |
07:00 |
7 pm |
19:00 |
|
8 am |
08:00 |
8 pm |
20:00 |
|
9 am |
09:00 |
9 pm |
21:00 |
|
10 am |
10:00 |
10 pm |
22:00 |
|
11 am |
11:00 |
11 pm |
23:00 |
So what's military time?
In the US, 24-hour time is often called military time,
because the armed forces use it. It's the same system with a couple of small
differences in style. It's usually written without the colon, like 0600 or
1730, and it's said out loud as "oh six hundred" or "seventeen
thirty". Midnight is written 0000.
Outside the US, nobody really calls it military time. It's
just the time. Hospitals, airlines, railways and emergency services around the
world use it because a mistake between morning and evening can be serious.
Who uses which format
Most of the world uses 24-hour time for anything official:
timetables, tickets, schedules, government forms. In everyday conversation,
it's a mix. People in many countries, including the UK, Australia, India and
much of the Arab world, happily use both, writing 24-hour time and saying
"half five" or "seven in the evening" out loud.
The US and Canada lean most heavily on the 12-hour clock in
daily life, which is exactly why American visitors tend to find 24-hour time
confusing at first.
The 12 am and 12 pm mix-up
This is the one that causes real problems. Is 12 am midnight
or noon?
12 am is midnight. 12 pm is noon. But plenty of people get
it backwards, and even printed schedules sometimes get it wrong.
Midnight has another trap too. If something is due "at
midnight on Friday", does that mean the start of Friday or the end of it?
People read it both ways.
The fix is to avoid the ambiguity entirely:
- Write
"12 noon" or "12 midnight" instead of am or pm.
- In
24-hour time, use 12:00 for noon and 00:00 for midnight.
- For
deadlines, use 23:59 on the day you mean, like "Friday 23:59".
Nobody can misread that.
Switching your devices to 24-hour time
If you want to get used to it, the fastest way is to switch
your phone and computer over for a couple of weeks.
- iPhone:
Settings > General > Date & Time, then turn on 24-Hour Time.
- Android:
usually Settings > System > Date & time, then turn on "Use
24-hour format".
- Mac:
System Settings > General > Date & Time, then turn on 24-hour
time.
- Windows
11: Settings > Time & language > Language & region >
Regional format, then change the time format to one that uses HH (for
example HH:mm).
WakeMode's Fullscreen Clock and World Clock both
have a 12/24-hour switch too. If you're getting used to 24-hour time, putting
the Fullscreen Clock on a spare screen in 24-hour mode is a surprisingly quick
way to learn it.
24-hour time looks strange for about a week. After that,
you'll probably wonder why anyone needs am and pm at all.