Phone number regex

Regex patterns for phone numbers: North American (NANP) with optional formatting, and international E.164. Tested examples and caveats.

Pattern

/^(?:\+?1[-. ]?)?$?([2-9][0-9]{2})$?[-. ]?([2-9][0-9]{2})[-. ]?([0-9]{4})$/

Matches

^\+[1-9]\d{1,14}$

The NANP pattern enforces that area codes and exchanges cannot start with 0 or 1.
E.164 is the storage format recommended by the ITU: a + followed by up to 15 digits and no spaces. Normalise user input to it before saving.
For real validation across countries, use a library such as Google's libphonenumber — numbering plans change.

const re = /^(?:\+?1[-. ]?)?\(?([2-9][0-9]{2})\)?[-. ]?([2-9][0-9]{2})[-. ]?([0-9]{4})$/;
re.test(value); // true or false

import re

bool(re.fullmatch(r'(?:\+?1[-. ]?)?\(?([2-9][0-9]{2})\)?[-. ]?([2-9][0-9]{2})[-. ]?([0-9]{4})', value))

The live tester adds the g and m flags so every line is checked separately.

How do I strip formatting before validating?

Remove everything except digits and a leading plus: value.replace(/[^\d+]/g, ""), then test against the E.164 pattern.