3v4l.org

run code in 300+ PHP versions simultaneously
<?php ob_start(); $time = microtime(1); $i = 0; while($i++ < 100000) echo'abcdef','abcdef','abcdef','abcdef','abcdef','abcdef','abcdef','abcdef'; ob_end_clean(); echo (microtime(1)-$time)." seconds for commas"; echo "\n"; ob_start(); $time = microtime(1); $i = 0; while($i++ < 100000) echo'abcdef'.'abcdef'.'abcdef'.'abcdef'.'abcdef'.'abcdef'.'abcdef'.'abcdef'; ob_end_clean(); echo (microtime(1)-$time)." seconds for dot";

preferences:
36.36 ms | 402 KiB | 5 Q