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Military time

Convert both ways, add or subtract hours from a time, and get the hours between two times, overnight included.

1 Convert

--:-- military
--:-- standard

Type a time in either form.

2 Add or subtract

--:-- military
--:-- standard

Enter a start time.

3 Hours between

--:-- hours and minutes
-- decimal hours

Enter both times.

If the second time is earlier on the clock than the first, it is counted as the next occurrence, so the span runs through midnight.

Military time reference

Standard 12-hour time and the 24-hour time it is written as.

Reference · 12-hour to 24-hour

StandardMilitaryStandardMilitary
1:00 AM01001:00 PM1300
2:00 AM02002:00 PM1400
3:00 AM03003:00 PM1500
4:00 AM04004:00 PM1600
5:00 AM05005:00 PM1700
6:00 AM06006:00 PM1800
7:00 AM07007:00 PM1900
8:00 AM08008:00 PM2000
9:00 AM09009:00 PM2100
10:00 AM100010:00 PM2200
11:00 AM110011:00 PM2300
12:00 PM noon120012:00 AM midnight0000

Good to know

Midnight has two spellings. 0000 marks the start of a day and 2400 marks the end of the same day, so 2400 Monday and 0000 Tuesday are the same instant written two ways. This page reads either one and always prints 0000, because that is what clocks, time clocks, and most charting systems show. If your unit or your form requires 2400 for an end-of-day entry, write it that way on the form.

Why charting uses 24-hour time. A time written as 7:30 in a record is not a fact, it is a guess: morning meds and evening meds look identical on paper once the AM or PM is dropped, smudged, or never written. In 24-hour time, 0730 and 1930 cannot be confused with each other, every time is exactly four digits, and times sort correctly when the record is read in order. That is why hospitals, EMS, aviation, and the military all write times this way.

A bare number is read as 24-hour time. Type 730 and this page reads 0730, because that is the form the digits are already in. Add pm when you mean the evening, so 730pm becomes 1930. Anything that is not a readable time says so instead of guessing.

The calculators ignore dates and daylight saving. Adding 6 hours to 1930 gives 0130 the next day, and this page tells you it crossed midnight, but it does not track which date that is. On the two nights a year when the clocks change, a span measured across the shift will be off by an hour.

Check for yourself that nothing is sent anywhere

You don't have to take our word for it. Every browser has a built-in panel that shows everything a page sends or receives over the internet. On a computer (this doesn't work on a phone):

  1. Press F12, or right-click anywhere on this page and choose Inspect.
  2. In the panel that opens, click the Network tab.
  3. Now use the tool: type a time and watch the readouts update.
  4. Watch the Network list. Nothing appears, because the times you typed are never sent anywhere. The math runs entirely on your own computer.