3v4l.org

run code in 150+ php & hhvm versions
Bugs & Features
<?php $yr="2009"; $week="01"; $day="Monday"; $day=date("D",strtotime($day)); echo date("Y-m-d", strtotime($yr."W".$week."D ".$day)-86000);; ?>
Output for 5.2.0 - 5.6.28, hhvm-3.10.0 - 3.13.2, 7.0.0 - 7.1.0
2008-12-31
Output for 5.1.0 - 5.1.6
2008-12-27
Output for 5.0.0 - 5.0.5
2008-12-20
Output for 4.3.0 - 4.4.9
1969-12-31