A better RegEx pattern for matching e-mail addresses

UPDATE: Also read Stefan Esser’s post: Holes in most preg_match() filters.

A few weeks ago, I posted a regular expression pattern for matching e-mail addresses.

Below is a more refined version.

^[-+.\w]{1,64}@[-.\w]{1,64}\.[-.\w]{2,6}$

Just as with the previous pattern, this one will match most valid e-mail addresses including:

• Addresses with periods and plus signs (e.g. ‘tiffany.brown’ or ‘hotc0derch1ck+todolist’)
• Top-level British and Australian domain names such as ‘.co.uk’ and ‘.com.au’
• New top-level domains such as ‘.museum’ and ‘.travel’

This pattern takes advantage of the \w character type. It’s a simpler way of waying “a – z (both upper and lower case), 0 – 9 and the underscore character” (though for many languages, \w means any alphanumeric character).

It also checks to see whether a user or domain name contains at least one, but no more than 64 alphanumeric characters. Sixty-four is the maximum character length for user and domain names under SMTP.

This pattern should work with most regular expression engines.

Recommended reading: Mastering Regular Expressions by Jeffrey E. F. Friedl