A few regex examples for validating common phone number formats

Regex Phone Validation

<?php

//regex for 7 or 10 digit number, delimiters are spaces, dashes, or periods:
^(?:(?:\+?1\s*(?:[.-]\s*)?)?(?:(\s*([2-9]1[02-9]|[2-9][02-8]1|[2-9][02-8][02-9]‌​)\s*)|([2-9]1[02-9]|[2-9][02-8]1|[2-9][02-8][02-9]))\s*(?:[.-]\s*)?)?([2-9]1[02-‌​9]|[2-9][02-9]1|[2-9][02-9]{2})\s*(?:[.-]\s*)?([0-9]{4})$

//same regex as above, but for 10 digit number only
^(?:(?:\+?1\s*(?:[.-]\s*)?)?(?:(\s*([2-9]1[02-9]|[2-9][02-8]1|[2-9][02-8][02-9]‌​)\s*)|([2-9]1[02-9]|[2-9][02-8]1|[2-9][02-8][02-9]))\s*(?:[.-]\s*)?)([2-9]1[02-9]‌​|[2-9][02-9]1|[2-9][02-9]{2})\s*(?:[.-]\s*)?([0-9]{4})$

//this regex will not allow the preceeding 1 at the beginning of the phone number
^(?:(?:(\s*\(?([2-9]1[02-9]|[2-9][02-8]1|[2-9][02-8][02-9])\s*)|([2-9]1[02-9]|[2‌​-9][02-8]1|[2-9][02-8][02-9]))\)?\s*(?:[.-]\s*)?)([2-9]1[02-9]|[2-9][02-9]1|[2-9]‌​[02-9]{2})\s*(?:[.-]\s*)?([0-9]{4})$



?>