Military Time Converter
Converts between the 24-hour clock and 12-hour AM/PM, including the midnight and noon traps.
Last updated
Your details
As HH:MM, or 1345.
Result
- 12-hour time
- 1:45 PM
- 24-hour time
- 13:45
- Minutes since midnight
- 825
- Decimal hours
- 13.7500
13:45 on the 24-hour clock…
Hours 13–23 lose 12 and become PM. 00 becomes 12 AM.
13 − 12 = 1, PM
1:45 PM
Formula — written step by step
13:45 on the 24-hour clock…
Hours 13–23 lose 12 and become PM
13 is greater than 12
13 − 12 = 1
Afternoon, so PM
1:45 PM
The awkward cases are the ends. Midnight is 00:00 on the 24-hour clock but 12:00 AM on the 12-hour one, and noon is 12:00 on both but PM. The 12-hour clock has no zero, which is what makes the conversion irregular rather than a plain subtraction.
A worked example
The midnight and noon traps
- 00:30
- thirty minutes after midnight
- 12:30
- thirty minutes after noon
- 00:30 → hour 0 has no 12-hour zero
- → 12:30 AM
- 12:30 → hour 12 stays 12
- → 12:30 PM
Both become 12:30 — one AM, one PM
This is why "12 AM" and "12 PM" cause so much confusion, and why timetables and contracts often write "12 midnight" and "12 noon" instead, or shift an appointment to 11:59 or 12:01 to remove all doubt.
How to use this calculator
- Enter a 24-hour time as HH:MM, or in the bare four-digit form such as 1345.
- Read the 12-hour equivalent with its AM or PM marker.
- Switch the mode to convert the other way, choosing AM or PM explicitly.
- The minutes-since-midnight row is useful for sorting or comparing times programmatically.
Two ways of naming the same instant
The 24-hour clock runs from 00:00 to 23:59, giving every minute of the day a unique name. The 12-hour clock runs twice from 12 to 11, distinguishing the halves with AM and PM — ante meridiem and post meridiem, before and after midday.
Converting from 24-hour to 12-hour is subtraction for most of the day: hours 13 through 23 lose twelve and take PM. The exceptions are hour 00, which becomes 12 AM, and hour 12, which stays 12 and takes PM.
Why 12 AM and 12 PM confuse everyone
The problem is that the 12-hour clock has no zero. It counts 12, 1, 2 … 11 and then starts again, so the hour containing midnight is named 12 rather than 0. Strictly, 12 AM is midnight at the start of the day and 12 PM is noon.
Because so many people get this backwards, careful writing avoids both. Timetables use "12 noon" and "12 midnight"; contracts often specify 11:59 PM or 12:01 AM precisely so no reader has to decide. If a deadline says "12 PM", it is worth asking.
Where the 24-hour clock is standard
Most of the world uses the 24-hour clock in writing, and it is universal in aviation, medicine, the military and computing — anywhere an ambiguous time could be dangerous. In speech it is often read as four digits: 13:45 becomes "thirteen forty-five", and in military usage "thirteen forty-five hours".
The United States, Canada, Australia and a few others keep the 12-hour clock in everyday use, which is why converters like this one exist at all. Note that "military time" in the strict sense also carries a timezone letter — Z for UTC, giving "Zulu time" — which the bare 24-hour clock does not.
Formula & methodology
What this calculator assumes
- Follows the 24-hour clock as defined by ISO 8601, running 00:00 to 23:59.
- 12 AM is midnight at the start of the day and 12 PM is noon. Because this is so widely reversed, unambiguous writing avoids both.
- "Military time" strictly also carries a timezone letter, such as Z for UTC. The bare 24-hour clock does not.
Sources
- ISO 8601-1:2019, Date and time — Representations for information interchange, International Organization for Standardization, 2019.
The full 24-hour mapping
| 24-hour | 12-hour | 24-hour | 12-hour |
|---|---|---|---|
| 00:00 | 12:00 AM | 12:00 | 12:00 PM |
| 01:00 | 1:00 AM | 13:00 | 1:00 PM |
| 02:00 | 2:00 AM | 14:00 | 2:00 PM |
| 06:00 | 6:00 AM | 18:00 | 6:00 PM |
| 09:00 | 9:00 AM | 21:00 | 9:00 PM |
| 11:00 | 11:00 AM | 23:00 | 11:00 PM |
Note the two irregular rows. Every hour from 13 to 23 is simply twelve less, but 00 becomes 12 AM and 12 stays 12 PM — the only two that are not a plain subtraction.
Frequently asked questions
Is 12 AM midnight or noon?
12 AM is midnight, at the start of the day, and 12 PM is noon. Because this is so often reversed, writing "12 midnight" or "12 noon" is safer.
What is 13:00 in 12-hour time?
1:00 PM. Every hour from 13 to 23 is simply twelve less, with PM.
Why is it called military time?
Because armed forces adopted the 24-hour clock to remove any ambiguity from orders. Strictly, military time also appends a timezone letter, such as Z for UTC.
How do I say 24-hour times aloud?
Usually as four digits: 08:30 is "oh eight thirty" and 13:45 is "thirteen forty-five". Military usage adds "hours" at the end.