A 24 hour time clock chart turns a four-digit time into a 12-hour time. Find the hour in the left column, then read across. Minutes do not change. 17:40 is 5:40 PM because 17 minus 12 is 5, and the minutes stay :40.
The chart covers the day from 00:00 through 23:59. Written 24-hour time, such as 18:05, is not the same string as a spoken military-style form, such as “eighteen hundred hours.” Schedules, transport boards, shift lists, and digital displays use one or the other. Read the form the source actually uses.
How to use this 24 hour time clock chart
A 24-hour clock gives every hour its own number, from 00 through 23. A 12-hour clock repeats 1 through 12 and adds AM or PM. 07:00 is 7:00 in the morning, 12:00 is noon, and 19:00 is 7:00 in the evening.
Use the table in two steps. Locate the four-digit value. Read the 12-hour time beside it. The hourly rows stop at 23:00 because each row is the start of an hour. The minute examples below show the rest of the hour.
Written military time often drops the colon, so 18:05 and 1805 are the same minute. A spoken form may add “hours.” The wording is a local procedure, not a second clock. A 2015 copy of Army ATP 6-02.70 includes a time-zone appendix, not a minute-by-minute pronunciation chart. That appendix says military time runs from 0000 hours at midnight through 2359 hours, and it reads 1500Z as “fifteen hundred hours Zulu time.”
The complete 24 hour time clock chart
The first column keeps the leading zero. A system that expects four digits needs 04:30, not 4:30. The last column is a common spoken military-style form for the exact hour. On the hour, say the hour and then “hundred hours.” 00:00 is the exception people ask about: it is commonly spoken “zero hundred hours,” not “zero zero hundred hours.” With minutes, drop “hundred” and say the hour digits and then the minutes. 07:30 is “zero seven thirty,” and 08:05 is “zero eight zero five.” If a unit publishes a different wording, use that wording.
| 24-hour time | 12-hour time | Spoken military-style form |
|---|---|---|
| 00:00 | 12:00 midnight | zero hundred hours |
| 01:00 | 1:00 AM | zero one hundred hours |
| 02:00 | 2:00 AM | zero two hundred hours |
| 03:00 | 3:00 AM | zero three hundred hours |
| 04:00 | 4:00 AM | zero four hundred hours |
| 05:00 | 5:00 AM | zero five hundred hours |
| 06:00 | 6:00 AM | zero six hundred hours |
| 07:00 | 7:00 AM | zero seven hundred hours |
| 08:00 | 8:00 AM | zero eight hundred hours |
| 09:00 | 9:00 AM | zero nine hundred hours |
| 10:00 | 10:00 AM | ten hundred hours |
| 11:00 | 11:00 AM | eleven hundred hours |
| 12:00 | 12:00 noon | twelve hundred hours |
| 13:00 | 1:00 PM | thirteen hundred hours |
| 14:00 | 2:00 PM | fourteen hundred hours |
| 15:00 | 3:00 PM | fifteen hundred hours |
| 16:00 | 4:00 PM | sixteen hundred hours |
| 17:00 | 5:00 PM | seventeen hundred hours |
| 18:00 | 6:00 PM | eighteen hundred hours |
| 19:00 | 7:00 PM | nineteen hundred hours |
| 20:00 | 8:00 PM | twenty hundred hours |
| 21:00 | 9:00 PM | twenty-one hundred hours |
| 22:00 | 10:00 PM | twenty-two hundred hours |
| 23:00 | 11:00 PM | twenty-three hundred hours |
Minutes pass through unchanged:
- 00:15 is 12:15 AM.
- 07:30 is 7:30 AM.
- 12:45 is 12:45 PM.
- 18:05 is 6:05 PM.
- 23:59 is 11:59 PM.
Four rows are worth a second look. 00:00 is midnight at the start of a calendar day. 12:00 is noon. 13:00 is 1:00 PM, the first hour after noon. 23:00 is 11:00 PM, the last full hour before midnight.
Some schedules use 24:00 to mark the end of a day. It is not an hour after 23:00, and it is not a row in the 00–23 table. NIST’s time-of-day guidance uses 0000 for midnight at the beginning of a date and 2400 for the end of that date. When the date could be read either way, write the date beside the time.
How to read 24-hour time without a full conversion
From 00:00 through 11:59, keep the hour and use AM, and write 00 as 12. From 12:00 through 12:59, stay on 12 and use PM. From 13:00 through 23:59, subtract 12 and use PM. 17:40 is in that third range: 17 − 12 = 5, so it is 5:40 PM, and the minutes stay :40.
Keep the leading zero in a four-digit field. 04:30 can be said “four thirty,” and a formal reading may be “zero four thirty.” NIST says 12 a.m. and 12 p.m. should not be used, because noon is neither before nor after noon and midnight can sit on either side of a date. Write 00:00 midnight or 12:00 noon. The NIST Times of Day FAQs are the source for that warning.
How to convert 24-hour time to AM and PM
Use one method instead of memorizing 24 answers.
- Keep 00:00 through 11:59 as the same hour with AM. Write 00 as 12.
- Label 12:00 through 12:59 as PM. The hour stays 12.
- For 13:00 through 23:59, subtract 12 and add PM.
- Copy the minutes exactly.
Worked examples:
- 06:25 is 6:25 AM. The hour is before noon.
- 12:10 is 12:10 PM. The hour stays 12.
- 15:45 is 3:45 PM, because 15 − 12 = 3.
- 21:05 is 9:05 PM, because 21 − 12 = 9. The :05 does not change.
The reverse is short. From 1:00 PM through 11:59 PM, add 12 to the hour. 3:45 PM is 15:45. 9:05 PM is 21:05. Do not add 12 to 12 PM: 12:10 PM is 12:10. For an AM time, keep the hour, except that 12:30 AM is 00:30.
The 10 time conversions readers check most often
- 0100 is 1:00 AM. A spoken form is “zero one hundred hours.”
- 0730 is 7:30 AM. A four-digit reading is “zero seven thirty.”
- 1200 is 12:00 noon, not midnight.
- 1300 is 1:00 PM, the first hour after noon.
- 1600 is 4:00 PM, because 16 − 12 = 4.
- 1805 is 6:05 PM. The :05 is unchanged.
- 2000 is 8:00 PM. A spoken form is “twenty hundred hours.”
- 2130 is 9:30 PM. The 30 minutes stay.
- 2345 is 11:45 PM, because 23 − 12 = 11.
- 2359 is 11:59 PM, the last minute before 00:00 starts the next day.
“Eighteen hundred hours” is a spoken form of an exact hour. A timetable can just be read as “six PM.” 2200 is 10:00 PM, or “twenty-two hundred hours.”
Four mistakes that make 24-hour time harder than it is
Most mistakes sit on the boundaries: midnight, noon, and the step from 12 to 13.
- Subtracting 12 from 12:00. Subtraction starts at 13:00. 12:00 is noon. 12:30 is 12:30 PM.
- Mixing up midnight and noon. NIST treats 12 a.m. and 12 p.m. as ambiguous. Use the table below when the boundary matters.
- Dropping a leading zero. Write 04:30 when the source expects four digits. The zero marks the hour.
- Treating spoken and written forms as one system. 18:00 is written 24-hour time. “Eighteen hundred hours” is a spoken form of that hour. They name the same point in the day and they are not the same notation.
| Written value | Clear description | Why it matters |
|---|---|---|
| 00:00 | midnight | Start of a new calendar day |
| 12:00 | noon | Middle of the day |
| 12:01 | one minute after noon | Falls in the PM period |
| 24:00 | end-of-day label in some schedules | Not part of the standard 00–23 hourly sequence |
When a 24-hour clock is the better format
Use 24-hour time when an AM or PM label is easy to miss. Overnight shifts, transport timetables, and coordination across places are the usual cases. The hour numbers do not repeat, so 20:00 cannot be read as a morning hour.
A shift listed as 20:00–04:00 runs from 8:00 PM to 4:00 AM on the following day. Write the date beside it, because the shift crosses midnight. The format removes AM and PM. It does not remove the day. NBS Monograph 155 is a historical study of timekeeping. It does not change these conversion rules.
The online clock shows this device’s time, with seconds and the date. A 12h/24h control switches the display, and Customize has the same 12-hour and 24-hour choice. The displays are minimal, flip, analog, and scenic. The world clock uses that saved format for each city, with the local time, the date, and the current UTC offset. Neither page speaks a military form or converts a time you type. Use the table for the conversion. The complete guide to free online clocks and time tools maps the other pages.
