Military Time Conversion: 24-Hour to 12-Hour Clock
Reviewed by Jerry Croteau, Founder & Editor
Table of Contents
I was staring at a schedule that made me feel dumb
I was standing in the lumber aisle doing math on my phone and nothing was adding up. Not because the math was hard — it was because the delivery window said 16:30–18:00 and my brain kept trying to turn that into “uhh… late afternoon-ish?” and that’s not good enough when you’ve got a crew waiting and a forklift guy who’s already irritated.
I nodded like I understood. I didn’t.
So if you’re here because you’ve got a text that says 0705, or a work order that says 14:00, or your phone got bumped into 24-hour mode and now you’re squinting at it like it’s written in another language… yeah, same.
And once you get the hang of it, it’s honestly kind of boring — in a good way.
The quick conversion list I wish someone handed me
You don’t need a lecture. You need a cheat sheet you can use while you’re juggling real life.
Here’s the thing: 24-hour time (military time) runs from 00:00 to 23:59. 12-hour time runs from 12:00 AM to 11:59 PM. Same day, same minutes — just different labeling.
| 24-hour (military) | 12-hour (standard) | What it “feels” like |
|---|---|---|
| 00:00 | 12:00 AM | Midnight |
| 07:05 | 7:05 AM | Early morning |
| 12:00 | 12:00 PM | Noon |
| 13:40 | 1:40 PM | After lunch |
| 16:30 | 4:30 PM | Late afternoon |
| 23:15 | 11:15 PM | Late night |
But if you want the mental shortcut, it’s basically this:
- 00:xx is 12:xx AM (midnight hour).
- 01:xx to 11:xx stays the same, just add AM.
- 12:xx stays 12:xx PM (noon hour).
- 13:xx to 23:xx subtract 12 and add PM.
So why does everyone get this wrong? Because 12 is the weird one. People want 12:00 to behave like the others and it just… doesn’t.
Want a tool instead of memorizing anything? Use a converter and move on with your day:
The actual math (it’s almost insultingly simple)
Okay, so if you’re like me, you don’t trust a rule until you can see the math behind it. And the math is just “what hour are we in?” plus one annoying exception.
If 12:00 ≤ H < 24:00 → standard hour = (H == 12 ? 12 : H − 12), PM
So if your time is 18:45, the hour is 18. That’s ≥ 12, so it’s PM, and you do 18 − 12 = 6. Minutes stay 45. Result: 6:45 PM. That’s it — the minutes never change, which is a weird relief the first time you realize it.
But here’s where people trip: 00:10 isn’t “0:10 AM.” It’s 12:10 AM. And 12:10 isn’t AM at all — it’s 12:10 PM. I had no idea why that was true at first, I just accepted it because every phone on earth agrees.
If you’re converting a bunch of times (like a whole shift schedule), don’t do it in your head unless you enjoy the excessiveness of tiny mistakes. Convert it once with a calculator and copy/paste it into your notes. Seriously.
Also: if you’re trying to figure out how long something lasts (like 21:30 to 01:15), that’s a different problem — that’s time duration across midnight. For that, you’ll want a duration tool, not just a converter. If you’ve got one of those “it starts at 23:00 and ends at 02:00” situations, use
7 real-world conversions you’ll actually use (and why they matter)
I’m calling this a listicle because, honestly, lists are what you use when you’re in a hurry. You don’t want theory — you want “tell me what 1540 is.”
1) 00:00 → 12:00 AM
Midnight. Not 0 AM. If you’re setting alarms or logging something, this one matters.
2) 00:30 → 12:30 AM
Still “after midnight,” still AM. If you’re scheduling a pickup “just after midnight,” this is the one.
3) 07:00 → 7:00 AM
Morning is easy. No subtraction, just drop the leading zero and add AM.
4) 12:00 → 12:00 PM
Noon. This is the one that makes people argue in group chats for no reason.
5) 13:15 → 1:15 PM
Subtract 12. This is where the rule starts paying rent.
6) 16:30 → 4:30 PM
This is the “delivery window” classic. And yeah — that’s a lot of shingles if you miss it!
7) 23:59 → 11:59 PM
Last minute of the day. If a deadline says 23:59, don’t overthink it — it’s 11:59 PM.
And if you’re dealing with timestamps in logs or spreadsheets, you might also need to add or subtract minutes (like “start time plus 45 minutes”). That’s not military-time-specific, it’s just time math. For that kind of thing, I usually reach for
If you’re comparing two times (like “how many hours between 09:20 and 17:05?”), that’s a different calculator again:
And if you’re converting times while traveling or coordinating with someone remote, you’ll probably end up needing a zone conversion too (because 14:00 isn’t helpful if you don’t know whose 14:00). Here:
FAQ (the stuff people always ask me)
Is military time the same as 24-hour time?
Basically, yes for everyday use. People say “military time” and “24-hour clock” interchangeably. Some military formats drop the colon (like 1630 instead of 16:30), but the value is the same.
What does 0000 mean?
- 0000 = 00:00 in 24-hour format
- That converts to 12:00 AM (midnight) in 12-hour format
- If you see 2400, some systems use it to mean “end of day,” but a lot of software avoids it and uses 23:59 or 00:00 instead.
How do I convert 12:xx PM back to 24-hour time?
If it’s 12:xx PM, keep the hour as 12. Don’t add 12. So 12:45 PM → 12:45.
If it’s 1:xx PM through 11:xx PM, add 12 to the hour: 7:10 PM → 19:10.
If it’s 12:xx AM, that’s the weird one: 12:05 AM → 00:05.
If you’re doing this more than once a week, don’t “get good at it.” Just use the tool and move on:
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