Get month difference from two dates in php

I recently needed to calculate age in months ranging from prenatal to 5 years old (60+ months).

Neither of the answers above worked for me. The first one I tried, which is basically a 1 liner for deceze's answer

$bdate = strtotime('2011-11-04'); 
$edate = strtotime('2011-12-03');
$age = ((date('Y',$edate) - date('Y',$bdate)) * 12) + (date('m',$edate) - date('m',$bdate));
. . .

This fails with the set dates, obviously the answer should be 0 as the month mark (2011-12-04) hasn't been reached yet, how ever the code returns 1.

The second method I tried, using Adam's code

$bdate = strtotime('2011-01-03'); 
$edate = strtotime('2011-02-03');
$age = 0;

while (strtotime('+1 MONTH', $bdate) < $edate) {
    $age++;
    $bdate = strtotime('+1 MONTH', $bdate);
}
. . .

This fails and says 0 months, when it should be 1.

What did work for me, is a little expansion of this code. What I used is the following:

$bdate = strtotime('2011-11-04');
$edate = strtotime('2012-01-04');
$age = 0;

if($edate < $bdate) {
    //prenatal
    $age = -1;
} else {
    //born, count months.
    while($bdate < $edate) {
        $age++;
        $bdate = strtotime('+1 MONTH', $bdate);
        if ($bdate > $edate) {
            $age--;
        }
    }
}

$start = new DateTime('2020-01-01 00:00:00');
$end = new DateTime('2021-03-15 00:00:00');
$diff = $start->diff($end);

$yearsInMonths = $diff->format('%r%y') * 12;
$months = $diff->format('%r%m');
$totalMonths = $yearsInMonths + $months;

echo $totalMonths; // 14

$start = new DateTime('2020-01-01 00:00:00');
$end = new DateTime('2021-03-15 00:00:00');
$diff = $end->diff($start);

$yearsInMonths = $diff->format('%r%y') * 12;
$months = $diff->format('%r%m');
$totalMonths = $yearsInMonths + $months;

echo $totalMonths; // -14

In this article, we will see how to calculate the difference between 2 dates in PHP, along with understanding its implementation through the examples. Given two dates ie., start_date and end_date & we need to find the difference between the two dates.

Consider the below example:

Input: start_date: 2016-06-01 22:45:00 
       end_date: 2018-09-21 10:44:01
Output: 2 years, 3 months, 21 days, 11 hours, 59 minutes, 1 seconds
Explanation: The difference of 2 dates will give the date in complete format.

Method 1: Using date_diff() Function

This function is used to find the difference between two dates. This function will return a DateInterval object on the success and returns FALSE on failure.

Example: This example illustrates the use of the date_diff() function to calculate the difference between the 2 dates.

PHP

<?php

  $datetime1 = date_create('2016-06-01');

  $datetime2 = date_create('2018-09-21');

  $interval = date_diff($datetime1, $datetime2);

  echo $interval->format('%R%y years %m months');

?>

Output:

+2 years 3 months

Method 2: To use the date-time mathematical formula to find the difference between two dates. It returns the years, months, days, hours, minutes, seconds between two specified dates.

Example: In this example, we will be using the date-time mathematical formula to calculate the difference between the dates that will be returned in years, months, days, hours, minutes, seconds.

PHP

<?php

  $date1 = strtotime("2016-06-01 22:45:00");

  $date2 = strtotime("2018-09-21 10:44:01");

  $diff = abs($date2 - $date1);

  $years = floor($diff / (365*60*60*24));

  $months = floor(($diff - $years * 365*60*60*24)

                                 / (30*60*60*24));

  $days = floor(($diff - $years * 365*60*60*24 -

               $months*30*60*60*24)/ (60*60*24));

  $hours = floor(($diff - $years * 365*60*60*24

         - $months*30*60*60*24 - $days*60*60*24)

                                     / (60*60));

  $minutes = floor(($diff - $years * 365*60*60*24

           - $months*30*60*60*24 - $days*60*60*24

                            - $hours*60*60)/ 60);

  $seconds = floor(($diff - $years * 365*60*60*24

           - $months*30*60*60*24 - $days*60*60*24

                  - $hours*60*60 - $minutes*60));

  printf("%d years, %d months, %d days, %d hours, "

       . "%d minutes, %d seconds", $years, $months,

               $days, $hours, $minutes, $seconds);

?>

Output:

2 years, 3 months, 21 days, 11 hours, 59 minutes, 1 seconds

Method 3: This method is used to get the total number of days between two specified dates.

PHP

<?php

  $start_date = strtotime("2018-06-08");

  $end_date = strtotime("2018-09-19");

  echo "Difference between two dates: "

      . ($end_date - $start_date)/60/60/24;

?>

Output:

Difference between two dates: 103

PHP is a server-side scripting language designed specifically for web development. You can learn PHP from the ground up by following this PHP Tutorial and PHP Examples.

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