What Does 00:00 Mean?
Updated June 15, 2026
00:00 is midnight — the start of a new day. In 12-hour time, it is 12:00 AM. In military time, it is spoken as "zero hundred hours" or simply "zero hundred."
Direct answer
00:00 in 24-hour time is 12:00 AM in 12-hour time. It is midnight. The hour is 00, the minutes are 00, and the period is the very first minute of the day. See the full 00:00 time page for nearby conversions.
Why 00:00 looks strange
Most clocks never show 00. They go from 23:59 straight to 00:00, and then to 00:01. The 00 means "zero hours have passed since midnight." If you are used to 12-hour time, seeing a zero where you expect a 12 can throw you off at first.
But the logic is simple: 00:00 is the starting point. Everything after it counts upward — 00:01, 00:02, and so on until 23:59. Then the cycle resets.
00:00 vs 2400 — are they the same?
Both refer to midnight, but they are used in different ways:
00:00
Marks the start of a day. If your shift, event, or trip begins at midnight, the schedule says 00:00. This is the standard in most 24-hour contexts.
2400
Marks the end of a day. Some schedules and deadlines use 2400 to make it clear which day midnight falls on. "Due by 2400 Friday" means before Saturday starts.
In practice, most organizations that use 24-hour time stick to 00:00 and avoid 2400 entirely. If you see 2400 on a timetable, it means the same moment as 00:00 the following day.
Where you will see 00:00
| Context | How 00:00 appears |
|---|---|
| Flight confirmations | Departure time shown as 00:05 or 00:30 for red-eye flights |
| Train and bus schedules | First departure of the day often listed as 00:XX |
| Hospital shift logs | Night shift starts at 00:00, charts use 24-hour format |
| Hotel check-in systems | A booking that starts at midnight may show 00:00 |
| Event tickets | Midnight shows or concerts listed as 00:00 |
| Computer logs | Server and system timestamps always use 24-hour time |
How to say 00:00 out loud
In military and aviation contexts, 00:00 is spoken as "zero hundred hours" or simply "zero hundred." In civilian 24-hour time, you can just say "midnight" — that is what most people do.
If you see 00:30, say "zero thirty" or "twelve thirty AM." Both are understood. The four-digit pronunciation matters more in formal settings such as dispatch, air traffic control, and the military.