Military Time Converter

Military time is the 24-hour clock written as four digits with no colon and no AM or PM. The day starts at 0000, noon is 1200, and the last minute is 2359. The name comes from its use in the US armed forces; most of the world simply calls it the 24-hour clock and writes it with a colon, as 13:30. Its advantage is that no time can be mistaken for another: 0700 and 1900 never need AM or PM to tell them apart.

If the hour is 13 or more, subtract 12 and add PM: 1545 becomes 3:45 PM and 2210 becomes 10:10 PM. From 0100 to 1159, drop any leading zero and add AM: 0815 is 8:15 AM. Two hours need care. Hour 00 becomes 12 AM, so 0030 is 12:30 AM, and hour 12 stays 12 but takes PM, so 1215 is 12:15 PM. The minutes never change.

For PM times from 1:00 PM to 11:59 PM, add 12 to the hour: 4:20 PM becomes 1620. For AM times, pad the hour to two digits: 9:05 AM becomes 0905. Then remove the colon. Twelve o'clock is the exception in both halves of the day: 12:45 AM becomes 0045, and 12:45 PM stays 1245.

A common convention reads the hour as one number and the minutes as another, then adds hours: 1330 is thirteen thirty hours and 2145 is twenty-one forty-five hours. A leading zero is spoken, so 0600 is zero six hundred hours, and times on the hour use hundred. Minutes from 01 to 09 are usually read as zero five or oh five. These are conventions rather than rules, and usage varies between services, countries and units.

Often, but not always. Adding hours, as in fourteen hundred hours, is common in US military speech and widely imitated elsewhere. In everyday conversation it is frequently dropped, and aviation radio usually reads a time digit by digit, as one four zero zero. In writing, the four digits alone are enough.

Both are used, for the two ends of the same day. 0000 is the first moment of a day and 2400 is its end, so 2400 on 3 March is the same instant as 0000 on 4 March. Clocks show 0000. 2400 appears in timetables, rotas and opening hours, where "until 2400" makes it clear that the whole day is included. Because the two are easy to mix up, many organisations sidestep the question by writing 2359 or 0001 instead.

12:00 PM is noon, which is 1200 in military time. 12:00 AM is midnight, which is 0000. The labels feel backwards because the clock switches to PM at 12 noon even though it still reads 12, and the same happens at night, when 11:59 PM is followed by 12:00 AM. Because this trips up so many people, schedules often write 12 noon and 12 midnight instead, and military time avoids the problem entirely.

Zulu time is Coordinated Universal Time (UTC). The name comes from Z, the letter of the zero-offset military time zone, whose phonetic word is Zulu. Writing 1330Z means 13:30 UTC wherever the reader is, which is why aviation, weather forecasting and military operations use it to keep everyone on one clock. To get from local time to Zulu, subtract your UTC offset: 1330 at UTC+2 is 1130Z, and 1330 at UTC-5 is 1830Z.

Because AM and PM are easy to drop, mishear or misread, and in those settings a twelve-hour mistake matters. A dose charted for 8:00 could mean either end of the day, while 0800 and 2000 cannot be confused. Aviation adds UTC on top, so a flight that crosses time zones runs on one clock from departure to arrival. Emergency dispatch and many police services keep their logs in 24-hour time for the same reason.

It is the first hour of the day, the one a 12-hour clock writes as 12:00 AM to 12:59 AM. Military time keeps the hour at 00, so 12:15 AM is 0015 and 12:45 AM is 0045, said as zero zero fifteen hours and zero zero forty-five hours. It catches people out because on a 12-hour clock this hour starts with 12, the largest number on the dial, rather than with a zero.