0030 Military Time

0030 is half past midnight, 12:30 AM. The first two digits are the hour, the last two are the minutes, and the minutes are the same in every system: 30 stays 30. Only the hour needs attention: the hour is 00, which the 12-hour clock calls 12 AM. Keep the minutes.

Midnight at the start of the day. Four zeros, said “zero hundred”. It is the one hour civilians write as 12 and the military writes as 0, which is why 12:15 AM becomes 0015 rather than 1215.

0030 sits 0.5 hours after midnight. A standard eight-hour shift that starts at 0030 ends at 0830; a twelve-hour shift ends at 1230.

Every single minute of this hour is listed on the 0000 page.

Adding whole hours to military time is a plain sum until you pass 2359, then you subtract 24 and move to the next day. A shift from 0030 that lasts eight hours ends at 0830. For a shift with a break, the work hours calculator does the subtraction and accepts both formats.

Military to 12-hour. The hour is 00, which the 12-hour clock calls 12 AM. Keep the minutes. Keep the 30 minutes: 0030 is 12:30 AM.

12-hour to military. 12 AM is the odd one out: write the hour as 00, not 12. 12:20 AM is 0020. So 12:30 AM is 0030: no colon, no AM, four digits.

The common slip is writing “00:30 AM”, which mixes the two systems. 0030 is half past midnight; half past noon is 1230.

0030 is said “zero zero thirty”. With minutes attached, the word “hundred” disappears; “zero hundred thirty” is wrong, and so is “zero thirty hundred”. The leading zero is still spoken, which is what makes it sound military rather than civilian.

Minutes follow the same logic. 0005 is “zero zero zero five” and 0040 is “zero zero forty”. Single-digit minutes get a spoken zero, so the listener knows a digit is there.

About the word “hours”: in speech, “zero hundred hours” is everywhere, and nobody will correct you. In writing, Army Regulation 25-50 says the word is not used with military time, so a memorandum reads “at 0030”, not “at 0030 hours”.

On its own, 0030 is local time wherever it is written. When the four digits carry a letter, the letter is the time zone. Z stands for Zulu, which is UTC, and J (Juliet) means the local time of the person speaking. The table converts 0030Z to the four US zones, in standard time and in daylight saving time.

Eastern Time is four hours behind UTC from March to November and five hours behind the rest of the year, which is why one Zulu time maps to two possible local times. The other three zones follow the same pattern an hour further west each.

Midnight has a second spelling, 2400, used when it marks the end of a day rather than the start. The full rules, with a converter, are on the military time chart page.