1300 Military Time

1300 is 1:00 PM, one o’clock in the afternoon. On a 24-hour clock with a colon it is 13:00; in military style the colon goes and the four digits stand alone. The hour is 13 hours after midnight and 11 hours before the next one.

One in the afternoon, and the first hour where military time and the 12-hour clock part ways. From 1300 to 2359 you subtract 12 to get the civilian hour.

To read it, look at the first two digits: the hour is above 12, so subtract 12 and add PM: 13 − 12 = 1. The last two digits are minutes and never change, so 1325 is 1:25 PM and 1350 is 1:50 PM.

Military to 12-hour. Split the four digits into hours and minutes, the hour is above 12, so subtract 12 and add PM: 13 − 12 = 1. So 1315 becomes 1:15 PM and 1345 becomes 1:45 PM.

12-hour to military. 1 PM is a PM hour, so add 12: 1 + 12 = 13. 1:05 PM is 1305. Drop the colon and the AM or PM, and you have the four digits.

The mistakes worth knowing: “13:00 PM” is a mix of both systems and means nothing, because a 24-hour time already says which half of the day it is. And 1300 is not 13:00 AM; there is no 13 o’clock in the morning.

1300 is said “thirteen hundred”. The “hundred” stands in for the two zeros; nobody says “thirteen zero zero”. Numbers from ten upward are said as ordinary numbers: “thirteen hundred”, not “one three hundred”.

Minutes follow the same logic. 1305 is “thirteen zero five” and 1340 is “thirteen forty”. Single-digit minutes get a spoken zero, so the listener knows a digit is there.

About the word “hours”: in speech, “thirteen 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 1300”, not “at 1300 hours”.

On its own, 1300 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 1300Z 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.