Difference between 24:00 and 00:00?

Question

What is the difference between 24:00 clock and 00:00 clock. IMO 24:00 clock is the day before and 00:00 clock is the beginning of the new day. But I\'m not really convinced

Answer 1

24:00 is a valid time and it is not quite the same as 00:00 - its a full 24 hours ahead of 00:00

00:00 on the 25th December is the start of Christmas Day.

24:00 on the 25th December is the END of Christmas Day. You could say that it is 00:00 on Boxing Day.

A Boxing Day Sale might start at 00:00 on Boxing Day - and it might end at 24:00 on Boxing Day. Far more convenient than saying 23:59:59.

Answer 2

After 23:59 comes 0:00, not 24:00 Please see the code below, in php, as you put the 'php' tag:

echo date('G:i:s', mktime(0,0,0)) . "\n" ;
echo date('G:i:s', mktime(0,0,0)-1) . "\n" ;

It will display:

0:00:00
23:59:59

Answer 3

Let's convert 24 hour time to 12 hour time. If it's 11:59 PM, in 1 minute it would be 12:00 AM. AM refers to the beginning of the day, and PM refers to the end of the day. If you use 24:00, you would be referring to the end of the day (PM), and 12:00 PM is not at night. So use 00:00.

Answer 4

Just try it yourself (which you should have done with your question so the relation to PHP becomes more clear):

echo '00:00 - ', date('r', strtotime('00:00')), 
   "\n24:00 - ", date('r', strtotime('24:00'));

Gives the following output (Demo):

00:00 - Thu, 25 Oct 2012 00:00:00 +0000
24:00 - Fri, 26 Oct 2012 00:00:00 +0000

Next thing you could have done (and @Baba pointed to it already) is to just check some resources first like (as a very first step) Wikipedia.

Answer 5

The notation 24:00 mainly serves to refer to the exact end of a day in a time interval. The last minute of the day begins at 23:59 in the 24 hour time

From Wikipedia

24:00 = midnight (end of day) shown as start of next day
00:00 = midnight (start of day)

But really 24:00 = 00:00 ... no difference but due to compatibility issue i would recommend you use 00:00

Answer 6

The concept of 00:00 / 24:00 is a familiar one to me working in China - in my situation I have dealt with it in terms the coverage period of insurance policies:

An annual policy with an effective date of 01/OCT/2013 24:00 would give coverage from 1st October 2013 to 30th September 2014.

An annual policy with an effective date of 01/OCT/2013 00:00 would give coverage from 2nd October 2013 to 1st October 2014.