I use this:
PHP Code:
<?php
$uptime = @exec('uptime');
preg_match("/averages?: ([0-9\.]+),[\s]+([0-9\.]+),[\s]+([0-9\.]+)/", $uptime, $avgs);
$uptime = explode(' up ', $uptime);
$uptime = explode(',', $uptime[1]);
$uptime = $uptime[0] .', '. $uptime[1];
$start = mktime(0, 0, 0, 1, 1, date('Y'), 0);
$end = mktime(0, 0, 0, date('m'), date('j'), date('y'), 0);
$diff = $end - $start;
$days = @($diff / 86400);
$percentage = @($uptime / $days) * 100;
$load = $avgs[1] + $avgs[2] + $avgs[3];
$load = $load / 3;
$load = round($load, 3);
// $load holds the load.
?>
Either way works though.
Edit: *nix only ;)