Here is a simple function to convert Bytes to KB, MB, GB, TB :
# Size in Bytes
$size = 14903511;
# Call this function to convert bytes to KB/MB/GB/TB
echo convertToReadableSize($size);
# Output => 14.2 MB
function convertToReadableSize($size){
$base = log($size) / log(1024);
$suffix = array("", "KB", "MB", "GB", "TB");
$f_base = floor($base);
return round(pow(1024, $base - floor($base)), 1) . $suffix[$f_base];
}