When you go to google and it says, it took 0.000123 seconds to find 123134134 items, and you think to yourself, wow I wish I could see how long it takes to load my page, well now you can! this is another straight forward little piece of code.
<?
//top of your page
$gentime = microtime();
$gentime = explode(' ',$gentime);
$gentime = $gentime[1] + $gentime[0];
$pg_start = $gentime;
?>
<?
//end of your page
$gentime = microtime();
$gentime = explode(' ',$gentime);
$gentime = $gentime[1] + $gentime[0];
$pg_end = $gentime;
$totaltime = ($pg_end - $pg_start);
$showtime = number_format($totaltime, 4, '.', '');
echo("This page was generated in " . $showtime . " seconds");
?>