The military time 2130 is the equivalent of 9:30 p.m. Military time runs on the idea of a 24-hour clock rather than a 12-hour clock for which time is divided into a.m. and p.m. hours.
Military time is reported as a four-digit number with the first two digits referring to the hour and the second two digits referring to the minute. Though midnight in military time can be designated as either 0000 or 2400 hours, it is most often displayed as 0000 hours. One minute past midnight is 0001. A military reading of 1 a.m. is 0100 hours, but 1 p.m. is 1300 hours. One minute before midnight is 2359.