Military time explained
By Dexaloop · Updated 27 October 2026 · Checked against the sources listed below
Military time is the 24-hour clock written as four digits without a colon. The day runs from 0000 (midnight) to 2359 (one minute before the next midnight), so there is no AM or PM. To convert, times from 0100 to 1159 are the same as AM times, 1200 is noon, and for 1300 to 2359 you take away 12 to get the PM hour: 1630 is 4:30 PM. Going the other way, add 12 to any PM hour except 12 PM. Midnight is written 0000 at the start of a day and can be written 2400 at the end of one.
How military time is written
A military time always has four digits. The first two are the hour, from 00 to 23. The last two are the minutes, from 00 to 59.
- 7:05 AM is 0705. The leading zero is kept so there are always four digits.
- 12:00 noon is 1200.
- 9:45 PM is 2145.
- 12:20 AM, twenty minutes after midnight, is 0020.
Outside military use, the same clock is usually written with a colon, such as 21:45. The time is identical; only the punctuation differs.
The conversion rules
| 12-hour time | Rule | Military time |
|---|---|---|
| 12:00 AM to 12:59 AM | Hour becomes 00 | 0000 to 0059 |
| 1:00 AM to 11:59 AM | Same hour, add a leading zero if needed | 0100 to 1159 |
| 12:00 PM to 12:59 PM | Hour stays 12 | 1200 to 1259 |
| 1:00 PM to 11:59 PM | Add 12 to the hour | 1300 to 2359 |
The two rows people trip over are the 12 o'clock rows. Twelve in the 12-hour clock is the odd one out: 12 AM is the start of the day, so it becomes 00, and 12 PM is noon, so it stays 12.
Worked examples
From 12-hour to military
- 3:15 PM: PM and not 12, so add 12. 3 + 12 = 15. Answer: 1515.
- 8:40 AM: AM and not 12, so keep the hour and pad it. Answer: 0840.
- 12:05 AM: the 12 AM hour becomes 00. Answer: 0005.
- 12:50 PM: the 12 PM hour stays 12. Answer: 1250.
From military to 12-hour
- 1945: the hour 19 is 13 or more, so take away 12. 19 minus 12 = 7. Answer: 7:45 PM.
- 0610: the hour is 6, under 12. Answer: 6:10 AM.
- 0030: hour 00 is the 12 AM hour. Answer: 12:30 AM.
- 1200: noon, 12:00 PM.
A quick mental shortcut for 1300 to 1959: take 2 from the second digit of the hour. So 15 gives 3, 18 gives 6 and 19 gives 7. For 20 to 23 the shortcut does not work, so take 12 away as normal to get 8, 9, 10 and 11.
Midnight and noon: 0000, 1200 and 2400
The 12-hour clock has a known problem at 12. NIST, the US government's time and measurement laboratory, says plainly that "12 a.m. and 12 p.m. are ambiguous and should not be used." Its reason is that noon is neither before nor after noon, and midnight is both twelve hours before and twelve hours after it.
The 24-hour clock solves this. NIST describes using "0000 to refer to midnight at the beginning of a given day (or date) and 2400 to designate the end of a given day." So:
- A shift from 1600 to 2400 on 3 March ends at midnight as 3 March closes.
- A shift from 0000 to 0800 on 4 March starts at that same moment, as 4 March begins.
Both describe the same instant, seen from different days. Writing 2400 makes it clear that a deadline means the end of a day, not its start. NIST also suggests that for events on a particular date, writing 11:59 p.m. or 12:01 a.m. avoids any doubt. Times such as 2401 are not used; after 2359 the clock rolls over to 0000.
Full-hour chart
| Military | 12-hour | Military | 12-hour |
|---|---|---|---|
| 0000 | 12:00 AM (midnight) | 1200 | 12:00 PM (noon) |
| 0100 | 1:00 AM | 1300 | 1:00 PM |
| 0200 | 2:00 AM | 1400 | 2:00 PM |
| 0300 | 3:00 AM | 1500 | 3:00 PM |
| 0400 | 4:00 AM | 1600 | 4:00 PM |
| 0500 | 5:00 AM | 1700 | 5:00 PM |
| 0600 | 6:00 AM | 1800 | 6:00 PM |
| 0700 | 7:00 AM | 1900 | 7:00 PM |
| 0800 | 8:00 AM | 2000 | 8:00 PM |
| 0900 | 9:00 AM | 2100 | 9:00 PM |
| 1000 | 10:00 AM | 2200 | 10:00 PM |
| 1100 | 11:00 AM | 2300 | 11:00 PM |
Why the 24-hour clock helps with hours worked
Subtracting times is easier when there is no AM and PM to juggle. A shift from 0745 to 1615 is 16:15 minus 7:45: from 0745 to 1545 is 8 hours, and 1545 to 1615 is 30 minutes, so 8 hours 30 minutes. In 12-hour time you would first have to notice that 4:15 PM is later than 7:45 AM even though 4 is smaller than 7.
Night shifts still need care. From 2200 to 0600 the end time is smaller than the start, so add 24 to the end hour before subtracting: 30:00 minus 22:00 is 8 hours.
Seconds and time zones
Seconds do not change between the two clocks. 4:30:15 PM is 16:30:15, and only the hour is converted. Military time also says nothing about where you are: 1400 in one city and 1400 in another are different moments if the cities are in different time zones. On a rota or a booking that crosses zones, write the zone next to the time so nobody has to guess.
Common mistakes
- Adding 12 to 12 PM. 12:30 PM is 1230, not 2430.
- Writing 12 AM as 1200. 12:15 AM is 0015. 1200 is noon.
- Dropping the leading zero. 0905 written as 905 can be misread. Keep four digits.
- Taking 12 away from morning times. Only hours 13 to 23 need it. 1130 is 11:30 AM.
- Mixing 0000 and 2400 on the wrong day. 2400 on Friday and 0000 on Saturday are the same moment. Use the one that matches the day you mean.
For a quick answer, or a printable chart, the converter below accepts either format, including 2400 and the words noon and midnight.
Convert military time: tools.dexaloop.com/military-time-converter/. Free, no sign-up, and it runs on your device.
Questions
What is 1700 in military time?
1700 is 5:00 PM. Take 12 away from 17 to get 5, and since the hour is 12 or more, it is PM.
Is midnight 0000 or 2400?
Both are correct, for different moments. A day begins at 0000 and ends at 2400, so 2400 on Monday and 0000 on Tuesday name the same instant. NIST describes this use of the 24-hour clock to remove the confusion of 12 a.m. and 12 p.m.
What is 12:30 AM in military time?
0030. Times between midnight and 1 AM start with 00, because the hour after midnight is hour zero.
Does military time use a colon?
Military style usually writes the four digits with no colon, such as 1630. Most other 24-hour clocks write 16:30. Both mean the same time.
Why do people use military time at work?
It removes the AM and PM mix-up, which matters on shift rotas, logs and handovers. It also makes it easier to subtract times when working out hours.
Sources
This guide is general information, not legal, tax or financial advice. Rules change; check the official source for your own case. Found a mistake? Email support@dexaloop.com.