regex - What regular expression will match valid international phone numbers?

Question

I need to determine whether a phone number is valid before attempting to dial it. The phone call can go anywhere in the world.

What regular expression will match valid international phone numbers?

Answer 1

+(9[976]d|8[987530]d|6[987]d|5[90]d|42d|3[875]d|
2[98654321]d|9[8543210]|8[6421]|6[6543210]|5[87654321]|
4[987654310]|3[9643210]|2[70]|7|1)d{1,14}$

Is the correct format for matching a generic international phone number. I replaced the US land line centric international access code 011 with the standard international access code identifier of '+', making it mandatory. I also changed the minimum for the national number to at least one digit.

Note that if you enter numbers in this format into your mobile phone address book, you may successfully call any number in your address book no matter where you travel. For land lines, replace the plus with the international access code for the country you are dialing from.

Note that this DOES NOT take into account national number plan rules - specifically, it allows zeros and ones in locations that national number plans may not allow and also allows number lengths greater than the national number plan for some countries (e.g., the US).