Alternate name: Account number
Chances are you’ve noticed your primary account number every time you’ve taken a look at your credit or debit card.
How Primary Account Numbers Work
While the long string of numbers on your credit card may look random at first glance, primary account numbers are not assigned randomly. A primary account number is created by following a system set by the American National Standards Institute (ANSI). The ANSI system codes the numbers to identify the card issuer, network, and account, with the goal of preventing fraud and identity theft.
First Six Numbers
The first six numbers of a primary account number identify what credit card issuer or industry the card comes from. The first number in the sequence is known as the major industry identifier (MII). Here’s a breakdown of what the first number of a primary account number represents:
Next Five Numbers
The following five numbers refer to the bank identification number (BIN) or issuer identification number (IIN). These numbers indicate which credit card issuer provided the card and which network it belongs to.
Remaining Numbers
The remaining digits in a primary account number, excluding the very last number, identify the card’s individual account. This set of numbers can vary from nine to 12 digits. The final number is known as a “check sum” and represents whether or not a credit card number is valid. The check sum is generated by an algorithm that can detect errors when someone inaccurately transcribes a credit card number.
Primary Account Number vs. Account Number
Even though primary account numbers are commonly referred to as “account numbers,” it’s important not to confuse your debit card primary account number with your checking account number. The primary account number on your debit card is what enables you to make purchases, and it’s the number you’ll store on a website if you set a default payment card. However, your debit card’s primary account number is different than your checking account number.
