PHP- Adding And Subtracting Dates

Jan 6th, 2009
Maruf scribbled this post.

Here’s how you add and subtract dates from one another. For example, this simple code can calculate what the date will be 2 weeks before or after 1998-08-14 (yyyy-mm-dd).

Subtracting days from a date

The following example will subtract 3 days from 1998-08-14. The result will be 1998-08-11.

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$date = "1998-08-14";
$newdate = strtotime ( '-3 day' , strtotime ( $date ) ) ;
$newdate = date ( 'Y-m-j' , $newdate );
 
echo $newdate;

Subtracting Weeks from a date

The following example will subtract 3 weeks from 1998-08-14. The result will be 1998-07-24. Notice that the only difference in the code is the week statement.

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$date = "1998-08-14";
$newdate = strtotime ( '-3 week' , strtotime ( $date ) ) ;
$newdate = date ( 'Y-m-j' , $newdate );
 
echo $newdate;

Subtracting Months from a date

The following example will subtract 3 months from 1998-08-14. The result will be 1998-05-14. Notice that the only difference in the code is the month statement.

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$date = "1998-08-14";
$newdate = strtotime ( '-3 month' , strtotime ( $date ) ) ;
$newdate = date ( 'Y-m-j' , $newdate );
 
echo $newdate;

Subtracting Years from a date

The following example will subtract 3 years from 1998-08-14. The result will be 1995-08-14. Notice that the only difference in the code is the year statement.

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$date = "1998-08-14";
$newdate = strtotime ( '-3 year' , strtotime ( $date ) ) ;
$newdate = date ( 'Y-m-j' , $newdate );
 
echo $newdate;

Adding days, months, weeks and years from a date

There isn’t really much difference from subtracting and adding dates. To add dates, just use any of the examples above and replace the negative (-) with a positive (+) e.g. ‘+3 weeks’