Variàveis:
<?php
$starttime = microtime();
$startarray = explode(" ", $starttime);
$starttime = $startarray[1] + $startarray[0];
?>
<?php
$endtime = microtime();
$endarray = explode(" ", $endtime);
$endtime = $endarray[1] + $endarray[0];
$totaltime = $endtime - $starttime;
$totaltime = round($totaltime,5);
echo "This page loaded in $totaltime seconds.";
?>