Date & time
Military time converter
The conversion is trivial except at two moments of the day, and those two are where every mistake happens.
The conversion rule
Going from 12-hour to 24-hour:
- AM hours 1-11 — unchanged, just zero-padded. 7:45 AM becomes 0745.
- PM hours 1-11 — add 12. 7:45 PM becomes 1945.
- 12 AM — becomes 0000. Midnight.
- 12 PM — stays 1200. Noon.
Going back, subtract 12 from any hour above 12, and treat hour 00 as 12 AM.
The two that trip everyone
12 AM is midnight and 12 PM is noon. Most people get this backwards at least once, and the reason is that the labels are genuinely illogical: AM means ante meridiem, before midday, and PM means after midday. But midday itself is neither before nor after — it is the meridiem. Twelve o'clock has to be assigned somewhere, and the convention puts noon in PM.
This ambiguity is exactly why hospitals, airlines and the military use the 24-hour clock. "The flight leaves at 12 AM" is a sentence that has caused real people to miss real flights. "0000" is not ambiguous.
0000 or 2400
Both refer to midnight, but they mean different edges of it. 0000 is the start of a day; 2400 is the end of the preceding one. They are the same instant described from opposite sides.
ISO 8601 permits both but recommends 0000. Contracts and opening hours often use 2400 deliberately: "open until 2400 Friday" is clearer than "open until 0000 Friday", which reads as being shut all day. This converter normalises 2400 to 0000 while noting the distinction.
How it is spoken
Military convention reads the four digits, with "hundred" for a whole hour. 0745 is "zero seven forty-five", 1900 is "nineteen hundred hours", 0000 is "zero hundred hours". The word "hours" is generally only used on the whole hour.
A time zone letter may be appended: Z, spoken "Zulu", means UTC. So "1400Z" is 2pm UTC regardless of where the speaker is. That convention exists so coordinated operations across time zones have one unambiguous reference.
Where the 24-hour clock is standard
Most of the world uses it in writing for anything official — transport timetables, hospital charts, broadcast schedules — even where people speak in 12-hour form conversationally. The 12-hour clock in written form is largely a US, UK, Canadian and Australian habit. The term "military time" itself is mainly American; elsewhere it is simply the normal way to write a time.
Common questions
Is 12 AM midnight or noon?
Midnight. 12 PM is noon. The labels are genuinely confusing because midday is neither before nor after itself, which is exactly why the 24-hour clock exists.
What is the difference between 0000 and 2400?
They are the same instant seen from either side. 0000 starts a day, 2400 ends the previous one. ISO 8601 recommends 0000, but contracts often use 2400 because "open until 2400 Friday" is clearer than "until 0000 Friday".
How do I convert PM times to 24-hour?
Add 12 to the hour for 1 PM through 11 PM, so 7 PM becomes 1900. 12 PM is the exception and stays as 1200.
What does the Z mean in 1400Z?
Zulu time, which is UTC. Appending a zone letter makes the time unambiguous across regions, which is why it is standard in aviation and military communication.