A billing zip code is a specific numerical code used to pinpoint a geographical location tied to an individual or business for processing transactions. It is the zip code associated with the billing address you have on file for your credit or debit card. This zip code is used not only to mail bills and other information associated with your credit or debit card to your address but also in many cases as a security measure when identifying yourself to complete a transaction online or over the phone. When you make a purchase, the ZIP code you enter must match the ZIP code associated with your official cardholder address. The billing zip code is also used as a Card Verification Value, and it is checked against the billing address zip code that the credit card issuing bank has on file. You can find your billing zip code associated with your billing address for your credit or debit card by looking up your own address, checking your most recent credit card bill, or looking up your account information on the credit card company’s website.