3v4l.org

run code in 300+ PHP versions simultaneously
<?php $yr="2014"; $dif=2012-$yr;if($dif != 0) $dif=$dif+1; $week="01"; $day="Monday"; $day=date("D",strtotime($day)); echo date("Y-m-d", strtotime($yr."W".$week."D ".$day)-(86000*$dif));; echo $dif; ?>
Output for 5.2.0 - 5.2.17, 5.3.0 - 5.3.29, 5.4.0 - 5.4.45, 5.5.0 - 5.5.37, 5.6.0 - 5.6.28, 7.0.0 - 7.0.20, 7.1.0 - 7.1.25, 7.2.0 - 7.2.33, 7.3.0 - 7.3.33, 7.4.0 - 7.4.33, 8.0.0 - 8.0.30, 8.1.0 - 8.1.27, 8.2.0 - 8.2.17, 8.3.0 - 8.3.4
2014-01-04-1
Output for 5.1.0 - 5.1.6
2013-12-30-1
Output for 5.0.0 - 5.0.5
2013-12-23-1
Output for 4.3.0 - 4.3.11, 4.4.0 - 4.4.9
1970-01-02-1

preferences:
229.14 ms | 405 KiB | 363 Q