Military time is the 24-hour clock written without a colon: 0800 is 8:00am, 1300 is 1:00pm, 2359 is 11:59pm. Midnight is written 0000.
To convert an afternoon or evening time to the 12-hour clock, subtract 12 from the hours: 1830 becomes 6:30pm. To go the other way, add 12 to any pm hour: 9:15pm becomes 2115.
Zone letters
Military notation often adds a letter for the zone, where Z ("Zulu") means UTC. So 1400Z is 14:00 UTC. You can switch this whole site to 24-hour display using the toggle in the header.