How to Read and Convert 24-Hour Time
Updated June 17, 2026
The 24-hour clock runs from 00:00 (midnight) to 23:59 (one minute before the next midnight). To convert it to 12-hour time, you only need one rule: if the hour is 13 or higher, subtract 12 and add PM. Everything else follows from that. This guide covers every case, with examples, a full chart, and pronunciation tips.
The one rule you need
If the hour is 13 through 23, subtract 12 and add PM. If the hour is 00, it is 12 AM (midnight). If the hour is 01 through 11, add AM. If the hour is 12, it is 12 PM (noon). Minutes never change. Try the converter to check any time instantly.
The two systems side by side
Before diving into conversion rules, it helps to understand what each system actually is.
24-hour clock
- Runs 00:00 through 23:59
- No AM or PM labels
- Each hour appears once per day (06:00 = morning, 18:00 = evening)
- ISO 8601 international standard
- Used by: transportation, healthcare, military, most countries outside the US
12-hour clock
- Runs 12:00 AM through 11:59 AM, then 12:00 PM through 11:59 PM
- Uses AM (before noon) and PM (after noon)
- Each hour number appears twice (7:00 AM and 7:00 PM)
- Dominant in: US, Canada, Australia, Philippines, India
- Familiar from analog clocks and everyday speech
Step-by-step conversion: 24-hour to 12-hour
There are only four cases. Memorize these and you can convert any time instantly.
| Hour range | What to do | Example |
|---|---|---|
| 00:00 – 00:59 | Replace 00 with 12, use AM | 00:30 → 12:30 AM |
| 01:00 – 11:59 | Keep the hour, add AM | 07:45 → 7:45 AM |
| 12:00 – 12:59 | Keep 12, add PM (noon) | 12:00 → 12:00 PM |
| 13:00 – 23:59 | Subtract 12, add PM | 18:30 → 6:30 PM |
Quick reference: 13:00 = 1 PM, 14:00 = 2 PM, 15:00 = 3 PM, 16:00 = 4 PM, 17:00 = 5 PM, 18:00 = 6 PM, 19:00 = 7 PM, 20:00 = 8 PM, 21:00 = 9 PM, 22:00 = 10 PM, 23:00 = 11 PM.
Full conversion chart
| 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 |
| 07:00 | 7:00 AM | 19:00 | 7:00 PM |
| 09:00 | 9:00 AM | 21:00 | 9:00 PM |
| 11:00 | 11:00 AM | 23:00 | 11:00 PM |
For every time at 15-minute intervals, see the full time conversion chart. For a printable military-time version, see the printable military time chart.
How to say 24-hour time aloud
There are two conventions for speaking 24-hour time: civilian and military. Most people use the civilian style or simply convert to 12-hour in conversation.
Civilian style (used in Europe, transport, daily life)
Say the hour and minutes as two separate numbers. For 18:30, say "eighteen thirty." For 14:00, say "fourteen hundred" or simply "two o'clock" after converting mentally. In countries like France and Germany, people often convert to 12-hour in speech: a French person seeing 18:30 on a train ticket will usually say "six heures trente" (six thirty), not "dix-huit heures trente."
Military style (used in US/NATO forces, aviation, dispatch)
Read the time as four digits without a colon. Full hours use "hundred": 0600 is "zero six hundred hours," 1200 is "twelve hundred hours." Times with minutes drop "hundred": 1730 is "seventeen thirty hours." Midnight is "zero hundred hours." Full military time pronunciation guide.
Common times you will actually see
Converting back: 12-hour to 24-hour
The reverse conversion is equally simple:
- 12:00 AM through 12:59 AM → subtract 12 from the hour: 12:30 AM = 00:30
- 1:00 AM through 11:59 AM → keep the hour as-is: 9:15 AM = 09:15
- 12:00 PM through 12:59 PM → keep 12: 12:00 PM = 12:00
- 1:00 PM through 11:59 PM → add 12 to the hour: 7:30 PM = 19:30
Tip: A common mistake is writing 1:00 PM as 1:00 in 24-hour time. The correct format is 13:00, always with two digits for the hour. Never write single-digit hours in 24-hour time.