1730 Military Time

1730 is half past five in the evening, 5:30 PM. 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 above 12, so subtract 12 and add PM: 17 − 12 = 5.

Five in the afternoon, the end of the standard working day and, by search volume, the most looked-up military time of all.

1730 sits 17.5 hours after midnight. A standard eight-hour shift that starts at 1730 ends at 0130 the next day; a twelve-hour shift ends at 0530 the next day.

Every single minute of this hour is listed on the 1700 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 1730 that lasts eight hours ends at 0130. For a shift with a break, the work hours calculator does the subtraction and accepts both formats.

Military to 12-hour. The hour is above 12, so subtract 12 and add PM: 17 − 12 = 5. Keep the 30 minutes: 1730 is 5:30 PM.

12-hour to military. 5 PM is a PM hour, so add 12: 5 + 12 = 17. 5:05 PM is 1705. So 5:30 PM is 1730: no colon, no PM, four digits.

The common slip is writing “17:30 PM”, which mixes the two systems. 1730 cannot be a morning time, because 17 is past 12; the morning equivalent would be 0530.

1730 is said “seventeen thirty”. With minutes attached, the word “hundred” disappears; “seventeen hundred thirty” is wrong, and so is “seventeen thirty hundred”. It is the same words you would use for the number 17 followed by the number thirty.

Minutes follow the same logic. 1705 is “seventeen zero five” and 1740 is “seventeen forty”. Single-digit minutes get a spoken zero, so the listener knows a digit is there.

About the word “hours”: in speech, “seventeen 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 1730”, not “at 1730 hours”.

On its own, 1730 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 1730Z 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.