increment date by one month

Question

Let\'s say I have a date in the following format: 2010-12-11 (year-mon-day)

With PHP, I want to increment the date by one month, and I want the year to be automatica

Answer 1

Use DateTime::add.

$start = new DateTime("2010-12-11", new DateTimeZone("UTC"));
$month_later = clone $start;
$month_later->add(new DateInterval("P1M"));

I used clone because add modifies the original object, which might not be desired.

Answer 2

//ECHO MONTHS BETWEEN TWO TIMESTAMPS
$my_earliest_timestamp = 1532095200;
$my_latest_timestamp = 1554991200;

echo '<pre>';
echo "Earliest timestamp: ". date('c',$my_earliest_timestamp) ."\r\n";
echo "Latest timestamp: " .date('c',$my_latest_timestamp) ."\r\n\r\n";

echo "Month start of earliest timestamp: ". date('c',strtotime('first day of '. date('F Y',$my_earliest_timestamp))) ."\r\n";
echo "Month start of latest timestamp: " .date('c',strtotime('first day of '. date('F Y',$my_latest_timestamp))) ."\r\n\r\n";

echo "Month end of earliest timestamp: ". date('c',strtotime('last day of '. date('F Y',$my_earliest_timestamp)) + 86399) ."\r\n";
echo "Month end of latest timestamp: " .date('c',strtotime('last day of '. date('F Y',$my_latest_timestamp)) + 86399) ."\r\n\r\n";

$sMonth = strtotime('first day of '. date('F Y',$my_earliest_timestamp));
$eMonth = strtotime('last day of '. date('F Y',$my_earliest_timestamp)) + 86399;
$xMonth = strtotime('+1 month', strtotime('first day of '. date('F Y',$my_latest_timestamp)));

while ($eMonth < $xMonth) {
    echo "Things from ". date('Y-m-d',$sMonth) ." to ". date('Y-m-d',$eMonth) ."\r\n\r\n";
    $sMonth = $eMonth + 1; //add 1 second to bring forward last date into first second of next month.
    $eMonth = strtotime('last day of '. date('F Y',$sMonth)) + 86399;
}

Answer 3

 <?php
              $selectdata ="select fromd,tod  from register where username='$username'";
            $q=mysqli_query($conm,$selectdata);
            $row=mysqli_fetch_array($q);

            $startdate=$row['fromd']; 
            $stdate=date('Y', strtotime($startdate));  

            $endate=$row['tod']; 
            $enddate=date('Y', strtotime($endate));  

            $years = range ($stdate,$enddate);
            echo '<select name="years" class="form-control">';
            echo '<option>SELECT</option>';
            foreach($years as $year)
              {   echo '<option value="'.$year.'"> '.$year.' </option>';  }
                echo '</select>'; ?>

Answer 4

For anyone looking for an answer to any date format.

echo date_create_from_format('d/m/Y', '15/04/2017')->add(new DateInterval('P1M'))->format('d/m/Y');

Just change the date format.

Answer 5

You can use DateTime::modify like this :

$date = new DateTime('2010-12-11');
$date->modify('+1 month');

See documentations :

http://php.net/manual/fr/datetime.modify.php

http://php.net/manual/fr/class.datetime.php

Answer 6

All presented solutions are not working properly.
strtotime() and DateTime::add or DateTime::modify give sometime invalid results.
Examples:
- 31.08.2019 + 1 month gives 01.10.2019 instead 30.09.2019
- 29.02.2020 + 1 year gives 01.03.2021 instead 28.02.2021
(tested on PHP 5.5, PHP 7.3)

Below is my function based on idea posted by Angelo that solves the problem:

// $time - unix time or date in any format accepted by strtotime() e.g. 2020-02-29  
// $days, $months, $years - values to add
// returns new date in format 2021-02-28
function addTime($time, $days, $months, $years)
{
    // Convert unix time to date format
    if (is_numeric($time))
    $time = date('Y-m-d', $time);

    try
    {
        $date_time = new DateTime($time);
    }
    catch (Exception $e)
    {
        echo $e->getMessage();
        exit;
    }

    if ($days)
    $date_time->add(new DateInterval('P'.$days.'D'));

    // Preserve day number
    if ($months or $years)
    $old_day = $date_time->format('d');

    if ($months)
    $date_time->add(new DateInterval('P'.$months.'M'));

    if ($years)
    $date_time->add(new DateInterval('P'.$years.'Y'));

    // Patch for adding months or years    
    if ($months or $years)
    {
        $new_day = $date_time->format("d");

        // The day is changed - set the last day of the previous month
        if ($old_day != $new_day)
        $date_time->sub(new DateInterval('P'.$new_day.'D'));
    }
    // You can chage returned format here
    return $date_time->format('Y-m-d');
}

Usage examples:

echo addTime('2020-02-29', 0, 0, 1); // add 1 year (result: 2021-02-28)
echo addTime('2019-08-31', 0, 1, 0); // add 1 month (result: 2019-09-30)
echo addTime('2019-03-15', 12, 2, 1); // add 12 days, 2 months, 1 year (result: 2019-09-30)