finding days between two dates in php code example

Example 1: php calculate date difference

//get Date diff as intervals 
$d1 = new DateTime("2018-01-10 00:00:00");
$d2 = new DateTime("2019-05-18 01:23:45");
$interval = $d1->diff($d2);
$diffInSeconds = $interval->s; //45
$diffInMinutes = $interval->i; //23
$diffInHours   = $interval->h; //8
$diffInDays    = $interval->d; //21
$diffInMonths  = $interval->m; //4
$diffInYears   = $interval->y; //1

//or get Date difference as total difference
$d1 = strtotime("2018-01-10 00:00:00");
$d2 = strtotime("2019-05-18 01:23:45");
$totalSecondsDiff = abs($d1-$d2); //42600225
$totalMinutesDiff = $totalSecondsDiff/60; //710003.75
$totalHoursDiff   = $totalSecondsDiff/60/60;//11833.39
$totalDaysDiff    = $totalSecondsDiff/60/60/24; //493.05
$totalMonthsDiff  = $totalSecondsDiff/60/60/24/30; //16.43
$totalYearsDiff   = $totalSecondsDiff/60/60/24/365; //1.35

Example 2: php calculate weeks between two dates

function numWeeks($dateOne, $dateTwo){
    //Create a DateTime object for the first date.
    $firstDate = new DateTime($dateOne);
    //Create a DateTime object for the second date.
    $secondDate = new DateTime($dateTwo);
    //Get the difference between the two dates in days.
    $differenceInDays = $firstDate->diff($secondDate)->days;
    //Divide the days by 7
    $differenceInWeeks = $differenceInDays / 7;
    //Round down with floor and return the difference in weeks.
    return floor($differenceInWeeks);
}

$numOfWeek = numWeeks('2021-01-21', '2021-01-28');