Bytes convert menggunakan PHP

Assalammualaikum wr. wb
Kali ini gue mau berbabagi ilmu lagi neh.
hehehe baekan
Seperti pada judul di atas, taukan artinya convert??
Kalo ga ngerti search aja di paman Google
Here we go..

<?php
function test($var1, $var2) {
if ($var2 == "kb") {
$kb = ($var1/1024*100000)/100000;
$var1 = $kb;
echo $var1." ".$var2;
}
elseif ($var2 == "mb") {
$mb = ($var1/1048576*100000)/100000;
$var1 = $mb;
echo $var1." ".$var2;
}
elseif ($var2 == "gb"){
$gb = ($var1/1073741824*100000)/100000;
$var1 = $gb;
echo $var1." ".$var2;
}
else {
echo "error";
}
}

echo test("1", "gb");
?>