What Is an Account Number?

An account number is the primary identifier for ownership of an account, whether a vendor account, a checking or brokerage account, or a loan account. An account number is used whether or not the identifier uses letters or numbers.

How an Account Number Works

At one time, it was common to use a Social Security number (SSN) as the primary identifier, particularly for employees (for payroll or human-resources identification). Because of the proliferation of identity theft, however, this practice has been all but eradicated. It is not a good idea to use a Social Security number for any type of account, or as a user name or password for electronic identification.

Example of an Account Number

In today's age of electronic payrolls, one of the most important account numbers is many people's lives is their checking account number. Payroll processing uses checking account numbers to set up electronic payments for employees.

To set up electronic payments or direct deposit, the easiest way to find that number is on a personal check (but there are other solutions if you don’t have checks).

The account number is located on the bottom of your check. There should be three sets of numbers in a special computer-readable font at the bottom:

  1. The first number on the left is your bank routing number
  2. The second (middle) number is your account number
  3. The third number is your check number

This traditional check layout applies to most personal checks, but business checks and bank-printed checks can have different formats.

Special Considerations

As online threats are on the rise a new breed of cybersecurity is also growing quickly. Means of encrypting and making it difficult for hackers to steal account numbers are taking the form of password managers, along with multi-factor authentication systems.

Password managers will often utilize a hard-to-hack master password, which unlocks a vault of a user’s account numbers and other sensitive data. Multifactor authentication often requires the use of another step (e.g., a fingerprint, voice activation, or time-sensitive code sent to a user’s cellphone, among others) to open an account—in addition to a password. These are just some of the means of protecting users’ account numbers in an increasingly vulnerable online environment.

Routing Number Versus Account Number

The routing number is a nine-digit number that identifies specific financial institutions within the United States. This number proves that the bank is a federal- or state-chartered institution and that it maintains an account with the Federal Reserve.

The account number on a check works together with the routing number. While the routing number identifies the financial institution, the account number—usually between eight and 10 digits—identifies an individual account holder's account. If somebody holds two accounts at the same bank, the routing numbers will, in most cases, be the same, but the account numbers will be different.

Key Takeaways

  • An account number is the primary identifier for ownership of an account, whether a vendor account, a checking or brokerage account, or a loan account.
  • An account number is used whether or not the identifier uses letters or numbers.
  • Payroll processing uses checking account numbers to set up electronic payments for employees.