PHP: Format US Phone Number to always be the same.

us-phone-format.php

<?php

$formatted_phone = preg_replace( '~.*(\d{3})[^\d]*(\d{3})[^\d]*(\d{4}).*~', '($1) $2-$3', $unformatted_number );

$formatted_phone = preg_replace( '~.*(\d{3})[^\d]*(\d{3})[^\d]*(\d{4}).*~', '$1.$2.$3', $unformatted_number );

$formatted_phone = preg_replace( '~.*(\d{3})[^\d]*(\d{3})[^\d]*(\d{4}).*~', '$1-$2-$3', $unformatted_number );