About Military Time
Hospitals, militaries, aviation, transit timetables, and most of the world outside the US run on the 24-hour clock for one reason: no AM/PM means no ambiguity — a medication chart reading 0800 and 2000 can't be misread twelve hours apart. The cost is a small mental conversion for anyone raised on the 12-hour dial.
Convert either direction, in any common format. Each result shows the digital form, the civilian equivalent, and the spoken military form (“seventeen thirty hours”) — the part that trips people up in the other direction at 0900 (“zero nine hundred”).
Adding up shift hours once the times are converted? That's the Hours to Decimal Calculator.
The Conversion Rules
Two directions, one rule each:
24-h → 12-h: hours ≥ 13 → subtract 12, add PM 0000 → 12:00 AM · 1200 → 12:00 PM 12-h → 24-h: PM (except 12 PM) → add 12 12 AM → 00
Worked examples: 1730 → 5:30 PM (17 − 12 = 5). 5:30 PM → 1730. 12:15 PM stays 1215; 12:15 AM becomes 0015. The only memorization is the noon/midnight pair — everything else is ±12.
Full Conversion Chart
The hours people actually look up:
| Military | Standard | Military | Standard |
|---|---|---|---|
| 0000 | 12:00 AM (midnight) | 1300 | 1:00 PM |
| 0100 | 1:00 AM | 1500 | 3:00 PM |
| 0600 | 6:00 AM | 1700 | 5:00 PM |
| 0900 | 9:00 AM | 1800 | 6:00 PM |
| 1100 | 11:00 AM | 2100 | 9:00 PM |
| 1200 | 12:00 PM (noon) | 2359 | 11:59 PM |
The PM rows all follow one pattern — first digit pair minus 12 — which after a week of use stops being arithmetic and becomes recognition.
Midnight, Noon & Speaking It
Midnight gets two names: 0000 (the start of a new day, the usual form) and 2400 (the end of the old one) — timetables pick whichever makes the day assignment obvious, so a shift “ending 2400 Friday” unambiguously belongs to Friday. Noon is simply 1200, and the 12-hour clock's genuinely confusing “12 AM/12 PM” pair is exactly the ambiguity the 24-hour clock exists to kill.
Speaking: whole hours read as hundreds — 0900 is “zero nine hundred (hours)”, 1300 “thirteen hundred.” With minutes, read the digits: 1730 is “seventeen thirty.” Military usage appends “hours”; aviation and much international use skips it. Leading zeros are always pronounced, which is why movie sergeants bark “oh-six-hundred.”