The Complete Guide to 24-Hour Military Time
Military time, formally referred to internationally as the 24-hour time system (ISO 8601 standard), measures the day from midnight (0000) through 2359. Unlike the civilian 12-hour format that repeats the numbers 1 through 12 twice daily using AM (Ante Meridiem) and PM (Post Meridiem), military time assigns a distinct, unambiguous four-digit numerical value to every minute of the 24-hour day.
In critical industries where communication errors carry severe life-or-death consequences, including emergency medical services (EMS), hospital nursing rosters, air traffic control, maritime operations, and military logistics, 24-hour time is mandatory to prevent dangerous timing confusion between morning and evening shifts.
Official 24-Hour Military Time Conversion Chart
Review the complete 24-hour breakdown with exact military designations and official military phonetic pronunciations:
| Standard 12-Hour Time | Military Time (24h) | Official Military Pronunciation |
|---|---|---|
| 12:00 AM (Midnight) | 0000 Hours | Zero Hundred Hours |
| 1:00 AM | 0100 Hours | Zero One Hundred |
| 2:00 AM | 0200 Hours | Zero Two Hundred |
| 3:00 AM | 0300 Hours | Zero Three Hundred |
| 4:00 AM | 0400 Hours | Zero Four Hundred |
| 5:00 AM | 0500 Hours | Zero Five Hundred |
| 6:00 AM | 0600 Hours | Zero Six Hundred |
| 7:00 AM | 0700 Hours | Zero Seven Hundred |
| 8:00 AM | 0800 Hours | Zero Eight Hundred |
| 9:00 AM | 0900 Hours | Zero Nine Hundred |
| 10:00 AM | 1000 Hours | Ten Hundred |
| 11:00 AM | 1100 Hours | Eleven Hundred |
| 12:00 PM (Noon) | 1200 Hours | Twelve Hundred |
| 1:00 PM | 1300 Hours | Thirteen Hundred |
| 2:00 PM | 1400 Hours | Fourteen Hundred |
| 3:00 PM | 1500 Hours | Fifteen Hundred |
| 4:00 PM | 1600 Hours | Sixteen Hundred |
| 5:00 PM | 1700 Hours | Seventeen Hundred |
| 6:00 PM | 1800 Hours | Eighteen Hundred |
| 7:00 PM | 1900 Hours | Nineteen Hundred |
| 8:00 PM | 2000 Hours | Twenty Hundred |
| 9:00 PM | 2100 Hours | Twenty-One Hundred |
| 10:00 PM | 2200 Hours | Twenty-Two Hundred |
| 11:00 PM | 2300 Hours | Twenty-Three Hundred |
Calculating Overnight and Graveyard Shift Hours Across Midnight
One of the most frequent payroll discrepancies occurs when computing work hours for third-shift or night-shift workers whose shifts cross midnight. Standard automated spreadsheet formulas often produce negative numbers when the end time (e.g. 0600) is numerically lower than the start time (e.g. 2200).
To accurately compute cross-midnight military time manually, apply the two-phase timecard algorithm:
Frequently Asked Questions
What is military time and why is it used?
Military time is a 24-hour timekeeping system that runs continuously from 0000 (midnight) to 2359 (11:59 PM). It eliminates the AM and PM designations, preventing dangerous scheduling ambiguities in emergency services, aviation, healthcare, defense, and cross-midnight shift work.
How do you convert PM standard time to military time?
For any time between 1:00 PM and 11:59 PM, add 12 to the standard hour and remove the colon and PM marker. For example: 6:45 PM becomes (6 + 12 = 18) -> 1845 Hours. For 12:00 PM (noon), it remains 1200 Hours.
How do you convert AM standard time to military time?
For times between 1:00 AM and 11:59 AM, write the hour as two digits (adding a leading zero if under 10) followed by the minutes. For example, 7:30 AM is 0730 Hours. For 12:00 AM (midnight), the hour converts to 0000 Hours.
How do you calculate shift hours when a graveyard shift crosses midnight?
When a night shift starts before midnight and ends the next morning (for example, 2200 to 0600), subtract the start time from 2400 (midnight) to get hours worked on day 1 (2400 - 2200 = 2 hours), and add the morning end time (0600 = 6 hours). Total gross time is 2 + 6 = 8 hours, from which unpaid lunch break minutes are subtracted.