1100 Military Time

1100 is 11:00 AM, eleven o’clock in the morning. On a 24-hour clock with a colon it is 11:00; in military style the colon goes and the four digits stand alone. The hour is 11 hours after midnight and 13 hours before the next one.

Eleven in the morning, the last hour before noon and the last one the 12-hour clock labels AM.

To read it, look at the first two digits: the hour is below 12, so add AM: 11 o’clock in the morning. The last two digits are minutes and never change, so 1125 is 11:25 AM and 1150 is 11:50 AM.

Military to 12-hour. Split the four digits into hours and minutes, the hour is below 12, so add AM: 11 o’clock in the morning. So 1115 becomes 11:15 AM and 1145 becomes 11:45 AM.

12-hour to military. 11 AM keeps its number; it already has two digits, so nothing is added: 11:05 AM is 1105. Drop the colon and the AM or PM, and you have the four digits.

The mistakes worth knowing: “11:00 AM” is a mix of both systems and means nothing, because a 24-hour time already says which half of the day it is. And 1100 is not 11 PM; 11 PM is 2300.

1100 is said “eleven hundred”. The “hundred” stands in for the two zeros; nobody says “thirteen zero zero”. Numbers from ten upward are said as ordinary numbers: “eleven hundred”, not “one one hundred”.

Minutes follow the same logic. 1105 is “eleven zero five” and 1140 is “eleven forty”. Single-digit minutes get a spoken zero, so the listener knows a digit is there.

About the word “hours”: in speech, “eleven 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 1100”, not “at 1100 hours”.

On its own, 1100 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 1100Z 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.