detects suspicious phone numbers

  • Hi all,


    do you have an idea of a formula that could help me to detect suspicious phone numbers in excel?

    I have a list of phone numbers each with 10 digits.


    I am trying to detect numbers that might be fake following the last 8 digits not to be:

    a) repetitive XXX XXXX

    b) consecutive (12345678) or the other way arround (87654321), at least 3 digits consecutive to be considered suspicious

    c) patern XYZ XYZ

    d) patern XY XY XY XY

    e) includes date (XX08202020), so is has the 2020 number in the string.


    any idea could help me :)

    thank you

  • Instead of starting with a short list of suspicious patterns, you could filter your list using a list of all active area codes and central office exchange codes (aka CO codes). CO codes are the next 3 digits following the area code. Ex. 416.230 is the beginning of my cell number.

    You can then automatically rule out any numbers that don't start with 6 proper digits leaving you just the final four digits to analyze.


    The following two links will provide you with lists of all existing US and CDA area codes and exchanges. ( including landlines and cell numbers). Good luck!


    https://www.nationalnanpa.com/…ports_cocodes_assign.html - look for the one that says all states

    http://cnac.ca/data/COCodeStatus_ALL.zip - this is the Candadian list