## Faqts : Computers : Programming : Languages : PHP : Function Libraries

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### Entry

##### How do I calculate the difference between two dates to return the number of days?

Jun 16th, 2000 07:08
Marco Steinacher, Robert Brown, http://www.php.net/manual/html/function.mktime.html

```You can do this with the following statement:
\$diff=abs(mktime(0,0,0,\$month1,\$day1,\$year1)-mktime(0,0,0,\$month2,\$day2,
\$year2))/(86400);
Explication:
************
mktime() returns seconds since 1.1.1970 for the specified date.
Thus the difference mktime([date1])-mktime([date2]) tells us the
seconds between [date1] and [date2].
If we divide the absolute value of this difference by the number of
seconds per day (24*60*60=86400) we get the number of days between
[date1] and [date2].
Example:
********
We want to know the difference between 31.12.1999 and 01.03.2000.
The following code tells us the answer:
<?
\$diff=abs(mktime(0,0,0,12,31,1999)-mktime(0,0,0,3,1,2000))/(86400);
echo \$diff;
?>
The script-output is: 61
That is correct then:
1 day  (31.12.99)
+31 days (in Jan.00)
+29 days (in Feb.00)
---------
=61 days
=========```