Military Time vs. 24-Hour Clock: What Is the Difference?

Military time and the 24-hour clock count the same 24 hours, and the difference is style: military time writes 1830 with no colon and says “eighteen thirty hours,” while the 24-hour clock writes 18:30. Converting between them only adds or removes the colon.

The 5 Differences

Detail	Military time	24-hour clock
Written	1830	18:30
Colon	Never	Usually
Leading zero	Always (0730)	Usually (07:30), sometimes 7:30
Spoken	“eighteen thirty hours”	“eighteen thirty”
Zone letter	Often (1830Z)	Rarely; offsets such as +00:00 instead

Where Each Format Is Used

Military time appears in the armed forces, police and fire dispatch, hospitals and aviation, where times are spoken on radios and written in logs.

The 24-hour clock is the everyday format in most of Europe, Latin America, Africa and Asia, on timetables, phones and computers, and in the ISO 8601 international standard (for example 2026-11-11T18:30:00Z).

Midnight in Both Formats

Both formats write midnight as 0000 / 00:00 at the start of a day. Both also allow 2400 / 24:00 for the end of a day, such as opening hours “09:00–24:00.”

Seconds

The 24-hour clock adds seconds after a second colon: 18:30:45. Military style adds seconds after a colon: 1830:45.

Which One Should You Use?

• Use military time in military, medical and dispatch records, and anywhere a time is read aloud.
• Use the 24-hour clock in timetables, software, international emails and documents that follow ISO 8601.
• Use 12-hour time only for audiences that expect AM and PM.

Converting Between the Two

• 18:30 → remove the colon → 1830
• 0715 → add a colon → 07:15
• Both to 12-hour time → subtract 12 from hours 13–23 and add PM.

Use the 24-hour to 12-hour converter for colon times and the military time converter for 4-digit times.