3v4l.org

run code in 300+ PHP versions simultaneously
<?php $now = time(); for($i=0;$i<2000000;$i++) echo ""; $end = time(); echo date("H:i:s:u",$now); echo "\n"; echo date("H:i:s:u",$end); echo "\n"; echo $end-$now;

preferences:
26.06 ms | 402 KiB | 5 Q