Military time converter: 12-hour to 24-hour time and back, how it is spoken, time-zone letters with the Zulu equivalent, and a full-day chart.
By AdminDrafted with AI writing toolsUpdated Checked examples: 11
7:45 PM is 1945 in military time, said “nineteen forty-five hours”.
| 12-hour | Military | Spoken (English) |
|---|---|---|
| 12:00 AM | 0000 | zero zero hundred hours |
| 1:00 AM | 0100 | zero one hundred hours |
| 2:00 AM | 0200 | zero two hundred hours |
| 3:00 AM | 0300 | zero three hundred hours |
| 4:00 AM | 0400 | zero four hundred hours |
| 5:00 AM | 0500 | zero five hundred hours |
| 6:00 AM | 0600 | zero six hundred hours |
| 7:00 AM | 0700 | zero seven hundred hours |
| 8:00 AM | 0800 | zero eight hundred hours |
| 9:00 AM | 0900 | zero nine hundred hours |
| 10:00 AM | 1000 | ten hundred hours |
| 11:00 AM | 1100 | eleven hundred hours |
| 12:00 PM | 1200 | twelve hundred hours |
| 1:00 PM | 1300 | thirteen hundred hours |
| 2:00 PM | 1400 | fourteen hundred hours |
| 3:00 PM | 1500 | fifteen hundred hours |
| 4:00 PM | 1600 | sixteen hundred hours |
| 5:00 PM | 1700 | seventeen hundred hours |
| 6:00 PM | 1800 | eighteen hundred hours |
| 7:00 PM | 1900 | nineteen hundred hours |
| 8:00 PM | 2000 | twenty hundred hours |
| 9:00 PM | 2100 | twenty-one hundred hours |
| 10:00 PM | 2200 | twenty-two hundred hours |
| 11:00 PM | 2300 | twenty-three hundred hours |
Hours below 10 keep a leading zero.
Nineteen forty-five hours. On a radio net the digits are read one at a time: one niner four five.
Military time writes the hour from 00 to 23 followed by the minutes, as four digits with no colon: 7:45 PM is 1945 and 12:30 AM is 0030. To convert an afternoon time, add 12 to the hour; to go back, subtract 12 from any hour from 13 to 23 and write PM. Noon is 1200 and midnight at the start of the day is 0000.
Type a time either way, with AM or PM, with a colon or as four digits. The converter gives the military, 24-hour and 12-hour forms, how the time is said aloud ("nineteen forty-five hours"), the digit-by-digit radio form, and a chart of all 24 hours. A zone letter after the digits, such as 1945R for US Eastern Standard Time, is turned into the matching Zulu (UTC) time.
The letters are fixed whole-hour offsets from UTC and ignore daylight saving time, so the zone that matches a place changes when its clocks change.
For 1:00 PM to 11:59 PM, add 12 to the hour; AM hours keep their number, and 12 AM becomes 00. Then write four digits with no colon: 1:30 PM is 1330, 7:45 AM is 0745 and 12:15 AM is 0015. Noon is 1200.
Subtract 12 from hours 13 to 23 and add PM: 1300 is 1:00 PM, 1700 is 5:00 PM and 2145 is 9:45 PM. Hours 01 to 11 are AM, 1200 is noon, and 0000 is midnight at the start of the day.
| 12-hour meaning | Military notation | 24-hour clock |
|---|---|---|
| Midnight, start of day | 0000 | 00:00 |
| 1:00 AM | 0100 | 01:00 |
| 6:00 AM | 0600 | 06:00 |
| 7:45 AM | 0745 | 07:45 |
| Noon | 1200 | 12:00 |
| 1:30 PM | 1330 | 13:30 |
| 7:45 PM | 1945 | 19:45 |
| 11:15 PM | 2315 | 23:15 |
| Midnight, end of day | 2400 | 24:00 |
Leading zeros stay: six in the morning is written 0600, not 600. 2400 marks midnight at the end of a day, the same instant as 0000 on the next day, and no other time in hour 24 exists, so 24:15 is not a valid time.
Read the four digits as two pairs, usually followed by "hours": 1945 is "nineteen forty-five", 0600 is "zero six hundred" and 0030 is "zero zero thirty". Radio operators read each digit instead and say 9 as "niner", so 1945 becomes "one niner four five".
A letter after the time names its zone. Z, Zulu, is UTC; to convert a lettered time to Zulu, subtract the zone's offset. 0800H (Hotel, UTC+8) is 0000Z, and 1945Q (Quebec, UTC−4) is 2345Z.
The ACP 121(G) communication instructions set out the letter system. For regional clock rules with daylight saving, use the time zone converter.
A date-time group stamps the day, time, zone letter, month and year: 23:30 Romeo time on 31 December 2026 is 312330R DEC 26. Zulu is five hours later, 0430 on 1 January 2027, so the day, month and year all change: 010430Z JAN 27.
Payroll often needs hours as decimals, which means dividing the minutes by 60. 1945 is 19.75 hours and 0730 is 7.5, so a shift from 0730 to 1615 lasts 16.25 − 7.5 = 8.75 hours. For overnight shifts and breaks, use the hours calculator.
To add or subtract lengths of time, use the time duration calculator.
Checked against: Add 12 to a PM hour; spoken in hundreds per Navy BMR ch. 3; digit words and “niner” from ACP 125(G) Table 3-2
Checked against: AR 25-50 para 1-26: “1:37 p.m. civilian time is expressed as 1337 military time”
Checked against: Navy BMR (NAVEDTRA 14325) ch. 3: “0100 (1:00 a.m.) is spoken ‘zero one hundred’”
Checked against: Navy BMR ch. 3: “2315 (11:15 p.m.) is spoken ‘twenty three fifteen’”
Keep AM hours as they are with a leading zero, write 12 AM as 00, keep 12 PM as 12, and add 12 to any other PM hour. Then write the hour and minutes as four digits without a colon: 7:45 PM is 1945 and 6:05 AM is 0605. Army Regulation 25-50 gives 1:37 p.m. as 1337 and says the word "hours" is not written after military time.
In hundreds, pair by pair. The US Navy's Basic Military Requirements manual gives 0100 as "zero one hundred", 2000 as "twenty hundred" and 2315 as "twenty three fifteen"; "hours" is usually added in speech, as in ACP 125's "sixteen thirty hours". Official sources say "zero", not "oh". On a radio net, date-time groups and times in poor conditions are read digit by digit: one six three zero, with nine said "niner".
Both appear. The Navy's Basic Military Requirements manual uses 0000 for the start of a day and 2400 for its end. The Navy correspondence manual (SECNAV M-5216.5) runs times from 0000 to 2359, while Army Regulation 25-50 runs from 0001 to 2400. ACP 121, the Allied communications standard, advises writing 2359 or 0001 in messages to avoid the ambiguity.
Zulu is the military name for UTC, the zone letter Z. Letters A to M (J skipped) are UTC+1 to UTC+12, N to Y are UTC−1 to UTC−12, and J (Juliett) means the observer's local time (Army ATP 6-02.70, Table E-1). Washington, DC in winter is zone R, UTC−5, so 1945R is 0045Z the next day. The letters are whole-hour offsets; ATP 6-02.70 marks a half-hour zone with an asterisk, as in 0430D* for Afghanistan (UTC+4:30).
It is how military messages stamp a date and time: two digits for the day, four for the time, the zone letter, then the month's first three letters and the year's last two digits. ACP 121(G) gives 271630Z JUN 03 as 16:30 UTC on 27 June 2003. Switch on "Write a date-time group" under More options to build one, in your zone and in Zulu.
This calculator includes 11 worked examples with independently sourced answers. They run in the test suite, and you can run them here too.