0021 military time is 12:21 AM

12:21 AM in every format

12-hour clock	12:21 AM
24-hour clock	00:21
Military time	0021 hours
Military pronunciation	zero zero twenty-one hours
ISO 8601	T00:21:00
In words	Twenty-one minutes past midnight
Part of the day	Night
Minutes since midnight	21
Day progress	1.46%

Military time uses four digits without a colon and counts hours from 00 to 23. 0021 is pronounced “zero zero twenty-one hours”.

Hour 00 is the midnight hour, so write 12 and add AM: 00:21 → 12:21 AM.

When a time zone matters, the military adds a letter: 0021Z means 0021 in UTC, known as Zulu time.

0021 is 12:21 AM.

Say “zero zero twenty-one hours”.