Basics
Midnight in Military Time: Is It 0000 or 2400?
Midnight is 0000 at the start of a day and 2400 at the end. When to use each, what NIST says about 12 a.m., schedules and contracts, “zero dark thirty”, and why 2430 or 2500 are never valid.
By Free Military Time Calculator Team · · Updated
Midnight is 0000 in military time at the start of a day and 2400 at the end of a day. Both describe the same moment: Monday 2400 is Tuesday 0000. Most logs, clocks and computers write midnight as 0000, said “zero hundred hours.”
0000 vs. 2400: Same Moment, Different Date
0000 opens a date and 2400 closes one. U.S. Army MWR reference pages list 12:00 AM (midnight) as “0000 or 2400,” with 0000 for the beginning of a day and 2400 for the end.
| Situation | Use | Example |
|---|---|---|
| A new day starts | 0000 | “Lights on at 0000 on Monday” |
| A period ends at midnight | 2400 | “Store hours 0800–2400” |
| Logs, timestamps, digital clocks | 0000 | “Recorded 12 Nov, 0000” |
| Deadlines on a date | 2359 | “Submit by 2359 Friday” |
Why 12 A.M. Causes Mistakes
The National Institute of Standards and Technology (NIST) calls 12 a.m. and 12 p.m. ambiguous. A.m. and p.m. mean before and after noon, so noon is neither and midnight sits between two dates. NIST suggests 11:59 p.m. or 12:01 a.m. for contracts and deadlines. Military time removes the problem: 0000, 1200 and 2400 each mean one moment.
Midnight on Schedules and Contracts
A shift written “1600–2400” ends exactly at midnight, and the next shift starts at 0000. A deadline written “Friday 2400” ends as Friday ends, while “Friday 0000” is the start of Friday, a full day earlier. Many organizations write 2359 to remove any doubt about the date.
The Minutes After Midnight
The hour after midnight is hour 00:
- 12:01 AM → 0001
- 12:15 AM → 0015
- 12:30 AM → 0030, said “zero zero thirty”
- 12:59 AM → 0059
- 1:00 AM → 0100
“Zero Dark Thirty”
“Zero dark thirty” is military slang for an unspecified very early hour, before dawn. It is not an official time; the closest written form is 0030.
Times That Don’t Exist
Military time stops at 2359, or 2400 for the end of a day. Times such as 2430, 2500 or 2900 are not valid, because the hours run only from 00 to 23. A number such as “25 hours” is a duration, not a time of day.
Noon, for Comparison
Noon is 1200, said “twelve hundred hours.” 12 PM is noon (1200) and 12 AM is midnight (0000).
See every time from 0000 to 2359 on the military time chart, or open the 0000 military time page.