FORMAT GUIDE
How to Write
Military Time
Writing military time correctly is governed by four absolute rules: four digits, no colon, no AM/PM, and always a leading zero for hours before 1000. Get any one wrong and the format is technically incorrect — in formal contexts, that matters.
Core Format Rules
The Four Rules of Writing Military Time
Rule 1 — Always Four Digits
Military time is always written as exactly four digits. Hours occupy the first two digits, minutes the last two. There are no exceptions. 9:00 AM is written 0900, never 900.
Rule 2 — No Colon
Unlike standard time (3:00 PM) or the international 24-hour clock (15:00), military time uses no colon separator. The four digits are written as a solid block: 1500, not 15:00.
Rule 3 — No AM/PM
AM and PM suffixes are never used in military time. The hour number itself encodes whether it is morning or afternoon — 0800 is obviously morning, 2000 is obviously evening. Appending "AM" or "PM" is redundant and incorrect.
Rule 4 — Leading Zero for Early Hours
Hours from midnight through 9:59 AM begin with a zero: 0100, 0730, 0945. This preserves the four-digit structure and prevents misreading.
Format Checker
Right vs Wrong — Common Format Errors
These are the most frequent formatting mistakes found in written military time. Each incorrect form is followed by the correct version and an explanation of why the original was wrong.
| Incorrect | Correct | Error |
|---|---|---|
| 800 | 0800 | Missing leading zero |
| 08:00 | 0800 | No colon in written military time |
| 8:00 AM | 0800 | No AM/PM in military time |
| 1500: | 1500 | No trailing punctuation or colon |
| 15:00 | 1500 | 24-hour clock format, not military |
| 1800 PM | 1800 | Never append AM/PM |
| 0060 | 0100 | Minutes max out at 59 |
| 2400 | 0000 | Midnight is 0000, not 2400 |
| 900 | 0900 | Always four digits |
| 12:30 PM | 1230 | No colon, no PM suffix |
Minutes Included
Writing Military Time with Minutes
When minutes are not zero, they occupy the last two digits of the four-digit block. The same four rules apply — no colon, no AM/PM, four digits total, leading zero on early hours. Minutes are always two digits: 5 minutes past is written 05, never just 5.
| Military | Standard | Spoken |
|---|---|---|
| 0615 | 6:15 AM | Zero-six-fifteen |
| 0830 | 8:30 AM | Zero-eight-thirty |
| 1045 | 10:45 AM | Ten-forty-five |
| 1200 | 12:00 PM | Twelve-hundred hours |
| 1330 | 1:30 PM | Thirteen-thirty |
| 1505 | 3:05 PM | Fifteen-zero-five |
| 1730 | 5:30 PM | Seventeen-thirty |
| 2015 | 8:15 PM | Twenty-fifteen |
| 2359 | 11:59 PM | Twenty-three-fifty-nine |
ISO 8601 vs Military Time Format
The international standard ISO 8601 — used in software, databases, and international commerce — writes time as HH:MM:SS with colons, for example 15:30:00. This is the format used on train schedules in Germany, pharmacy receipts in Japan, and most software systems worldwide.
Military time specifically omits the colon: 1530 not 15:30. In casual use these are often interchanged, but in formal military and aviation contexts, the colon-free form is correct. If you see 15:00 written somewhere, it is 24-hour clock notation, not military time — the distinction can matter on official documents.
Common Confusion
Military Time vs the 24-Hour Clock
Most people use "military time" and "24-hour clock" interchangeably, and for practical purposes they refer to the same numbering system. The hours run from 0 to 23, midnight is zero, and noon is twelve. But the written format differs.
Military Time Format
- • No colon: 1500
- • No AM/PM suffix
- • Always exactly four digits
- • May append "hours" when spoken
- • Used in US/NATO military, aviation, EMS
24-Hour Clock Format
- • Colon separator: 15:00
- • No AM/PM suffix (same as military)
- • ISO 8601 standard form
- • Used internationally, in transport, healthcare
- • Common on European train timetables
In practice, if you write 1500 on a US medical chart, it's military time. If your flight confirmation shows 15:00, it's 24-hour clock format. The underlying time is identical. The format difference matters most in formal military orders, aviation communications, and legal medical documentation.
Usage in Context
Writing Military Time in Sentences
When writing military time inside a sentence or paragraph, the four-digit block stands alone. Some contexts append the word "hours" after the time; others — especially informal operational writing — omit it. In formal orders and logs, "hours" is standard.
Formal order: "The unit will depart at 0600 hours and reach the objective no later than 1400 hours."
Medical chart entry: "Morphine 4mg IV administered at 1423. Patient reported pain reduction by 1445."
Aviation log: "Aircraft departed 0845, arrived 1315. Total flight time: 4h 30m."
Casual operational use: "Brief at 0730, mission launches 0900, RTB by 1700."
Context Matters
Formal vs Informal Usage
Formal / Official Contexts
In official military orders, medical records, aviation logs, and legal documentation, precision is mandatory. Use the full spoken form with "hours" appended, maintain strict four-digit format, and never use colons or AM/PM.
- • Field orders and operations plans
- • Medication administration records (MAR)
- • Air traffic control communications
- • Legal incident reports and logs
- • Military training documents
Informal / Casual Contexts
In everyday workplace communication among people who use military time regularly, the format is still four digits and no colon, but "hours" is often dropped. Spoken contractions like "fifteen-hundred" are common.
- • Shift handoff notes between nurses
- • Team scheduling emails
- • Text messages between operators
- • Dispatching radio communications
Edge Cases
Special Times to Memorize
Midnight
0000
The start of a new day. Sometimes written as 2400 to denote the end of the previous day, but 0000 is standard for midnight as a start time.
Noon
1200
Noon is twelve-hundred, the 12th hour of the day. Not 0000 (that's midnight). Memorize: 1200 = noon, 0000 = midnight.
End of Day
2359
The last moment of a calendar day. One minute later becomes 0000 of the following day. Used in schedules to denote "end of day" boundaries.
Quick Reference: Format Checklist
- ✓ Four digits total (hours + minutes, no colon)
- ✓ Leading zero for hours 0100–0900
- ✓ No AM or PM suffix ever
- ✓ Minutes use two digits: 05, 30, 45 — never single digit
- ✓ Midnight = 0000, Noon = 1200
- ✓ "Hours" may be appended in formal writing: 1500 hours
- ✗ Never use a colon: 15:00 is 24-hour clock, not military