I found an online JS calculator and a PHP solution:
<?php
function DMStoDEC($deg,$min,$sec)
{
// Converts DMS ( Degrees / minutes / seconds )
// to decimal format longitude / latitude
return $deg+((($min*60)+($sec))/3600);
}
function DECtoDMS($dec)
{
// Converts decimal longitude / latitude to DMS
// ( Degrees / minutes / seconds )
// This is the piece of code which may appear to
// be inefficient, but to avoid issues with floating
// point math we extract the integer part and the float
// part by using a string function.
$vars = explode(".",$dec);
$deg = $vars[0];
$tempma = "0.".$vars[1];
$tempma = $tempma * 3600;
$min = floor($tempma / 60);
$sec = $tempma - ($min*60);
return array("deg"=>$deg,"min"=>$min,"sec"=>$sec);
}
?>