Military Time Converter (12-hour ↔ 24-hour clock)

Understanding the military time converter — concept and principle

This converter switches times between the 12-hour clock with AM and PM and the 24-hour clock, including military style written without a colon. It also gives the minutes since midnight and the time in decimal hours, and flags noon and midnight. Travellers, nurses, shift workers and anyone reading timetables use it.

PM hours: add 12 — with the default inputs: 1945.

How it is calculated

From 12-hour: 1 PM to 11 PM add 12 to the hour; 12 AM becomes 00 (midnight); 12 PM stays 12 (noon); other AM hours stay the same
From 24-hour: hours 13 to 23 subtract 12 and add PM; 00 becomes 12 AM
Military time = the same four digits without the colon (19:45 → 1945)
Minutes since midnight = hours × 60 + minutes; decimal hours = minutes ÷ 60

The principle

The 24-hour clock counts the hours of the day from 00 to 23, so no AM or PM label is needed and there is no ambiguity. AM and PM come from Latin ante meridiem and post meridiem, before and after noon. The US time service at NIST notes that "12 a.m." and "12 p.m." are easy to misread and suggests writing 12 noon, 12 midnight, or 00:00 for the start of a day and 24:00 for its end.

Worked example

Default: 7:45 PM.

PM and the hour is not 12, so add 12: 7 + 12 = 19: 19:45.
Military style: 1945, said "nineteen forty-five".
Back to 12-hour: 7:45 PM.
Minutes since midnight = 19 × 60 + 45 = 1,185; decimal hours = 19.75.
Note: — (not noon or midnight).

How to read the result

Decimal hours are useful for timesheets: 19.75 means 19 hours and 45 minutes, not 19 hours 75 minutes. To find the length of a shift, subtract start from end in minutes since midnight, adding 1,440 if the shift crosses midnight.

Common mistakes

Writing 12:30 AM as 12:30; in 24-hour time it is 00:30.
Adding 12 to 12 PM.
Reading decimal hours as hours and minutes (7.5 hours is 7:30).
Leaving off a leading zero in military time (0745, not 745).

Keep in mind: Some regions and services use local conventions. When a time matters, for example for medication or travel, confirm the format used.

Frequently asked questions

What is 7:45 PM in military time?

1945.

Is midnight 0000 or 2400?

0000 is the start of a day; 2400 is the end of the previous day.

What is 1300 in normal time?

1:00 PM.

Sources: NIST Time and Frequency Division, "Times of day" FAQ

Checked 9 Nov 2026. NIST Time and Frequency Division, “Times of day” FAQ (12 a.m./12 p.m. ambiguity; 0000 for midnight at the start and 2400 at the end of a day); a.m./p.m. = ante/post meridiem (before/after noon).

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