What Is A Routing Number? (2024)

If you look closely at the bottom left of a check, you’ll notice a string of nine numerals. Known as the bank routing number, this line of digits is an essential part of everyday financial life. You may not know your bank’s routing number by memory in the same way as your Social Security number or debit card PIN, but your bank routing number works behind the scenes of the banking system in important ways.

Your bank routing number helps you move money. It enables you to get paid and pay bills. And it helps the banking system process transactions. Anytime money needs to go into or out of your bank account, your bank routing number helps make it happen.

Here’s more info about bank routing numbers and how they work as part of the banking system.

What Is a Routing Number?

The bank routing number—often called the ABA routing number, where ABA stands for the American Bankers Association—is your bank’s special identification number. Just as individuals in the U.S. have a Social Security number or Taxpayer Identification Number, banks have ID numbers called routing numbers.

ABA routing numbers are symbols of quality and legitimacy. These numbers are issued only to federal or state-chartered financial institutions eligible to maintain an account at a Federal Reserve Bank. Your bank’s routing number proves that it’s a legitimate chartered financial institution to the banking system.

Bank routing numbers help banks recognize each other and help make transactions possible. These numbers also help ensure trust in the banking system. Sellers can have confidence that they will get paid with funds from a legitimate bank, and buyers can prove that their money is ready to go.

In the same way you might need to show your ID to make a purchase or cash a check, the bank routing number is your bank’s ID. It helps other banks, merchants and anyone who needs to send or receive money verify that the money routes to or from the right bank.

Bank routing numbers also help make sure that the banking system functions. These identifying numbers allow transactions to get processed more smoothly while avoiding confusion, delays or misunderstandings between buyers and sellers.

How Many Digits is a Routing Number?

An ABA routing number has nine digits. This nine-digit number has three components. The first four digits are the Federal Reserve Routing Symbol, the second four digits are the ABA institution identifier and the final digit is what’s called a check digit that is used to prevent transaction errors.

Where Is the Routing Number on a Check?

Your bank’s nine-digit routing number usually appears in the lower-left corner of every check in your checkbook.

The number to the right of the routing number is your checking account number. Be careful not to get these numbers confused since it could cause a delay in your payment or deposit.

Where to Find Bank Routing Numbers Without a Check

If you don’t have your checkbook handy or don’t use paper checks, there are a few other ways to get your bank routing number:

• Bank statements. Look at your latest bank statement. Most banks will list the ABA routing number as part of your account information that they send each month via mail or paperless electronic statements.
• Bank website or mobile app. Many banks prominently list their ABA routing numbers on their website and mobile app. Be aware that some banks have more than one routing number. Some big national banks may also have different routing numbers for other states.
• Call your bank. If you have any uncertainty about your bank’s routing number, you can also call your bank and ask the staff to confirm the correct ABA routing number.
• Use the ABA online lookup tool. The ABA website has a free ABA Routing Number Lookup tool to look up routing numbers for banks. However, you can only use this tool to look up two ABA routing numbers per day and up to 10 per month.

Types of Routing Numbers

Some banks maintain different routing numbers for paper checks, electronic or ACH (Automated Clearing House) transactions, though many institutions use the same number. If you want to obtain a routing number to set up a transaction, your bank may ask what type of transaction you wish to make or which kind of account you need a routing number.

ABA Routing Number

The ABA routing number, sometimes called the check routing number, helps banks easily exchange funds and process checks and other transactions.

ACH Routing Number

The ACH routing number, also called the electronic routing number, is used for electronic transactions. This may be the same as your bank’s ABA routing number.

If you need to make a wire transfer, your bank may have a different routing number for that type of transaction.

When You May Need Your Bank Routing Number

Generally, your bank’s ABA routing number isn’t something you need to use every day, and you only need to know or enter your ABA routing number for certain types of transactions, such as wire transfers or ACH transactions.

Here are a few types of transactions when you might need to obtain and enter your bank routing number:

• Wire transfers. Sending or receiving large amounts of money via wire, especially for international transactions. Banks often charge a fee for wire transfers.
• ACH deposits. If you have just started a new job and are signing up for direct deposit at work, you must provide your bank routing number and your bank account number.
• IRS direct deposits. If you are receiving a tax refund, the IRS will allow you to sign up to receive the money via direct deposit to your bank account via ACH. This is another occasion when you need to provide your bank routing number and account number. You also may receive your tax refund faster.
• Paying bills. If you are signing up to pay a bill online or signing up for a payment app like Venmo or other mobile payment apps, you may need to enter your bank routing number (and bank account number) to give the payee or the mobile app access to your bank account.
• Making deposits to retirement accounts or transfers to other banks. When you invest money for retirement, your investment manager or retirement plan provider will probably want you to use ACH deposits to transfer your money from your bank to your retirement savings each month. The same goes for transferring money between banks. If you have a high-yield online savings account, for example, at a different bank than your everyday checking account, you might need to set up the transactions via ACH transfer, and that requires your bank routing number.

ACH transfers are a fast, low-cost (often free) way to move money between banks.

Things You May Not Know About Bank Routing Numbers

• The bank routing number was first developed in 1910 by the American Bankers Association (ABA).
• Each bank may have up to four additional routing numbers beyond the “principal office number.”
• The ABA’s Routing Number Administrative Board manages the assignment of routing numbers.
• Each nine-digit routing number has three components:
  • Federal Reserve routing symbol. These are the first four digits of the routing number. If the first two numbers of a routing number are 00, the routing number is for a check or draft from the U.S. Government. Banks use routing numbers that start with the first digits of 01-12. Traveler’s checks have routing numbers that begin with 80. Most of the other first two-digit series are “reserved for future use,” determined by the ABA Routing Number Administrative Board.
  • ABA institution identifier. The next four digits are the unique identifier of the particular bank/financial institution.
  • Check digit. The last number is the check digit, which helps banks avoid transaction errors.

Bottom Line

Bank routing numbers are not something that most people think about in everyday banking transactions, but they serve an important purpose. These nine-digit numbers help banks identify each other, build trust in the banking system, avoid errors and delays and generally help everyone’s deposits and payments go where they need to go.

Next time you need your bank’s ABA routing number to set up a new account or complete a purchase, you’ll know where to find it: at the bottom of every check, on your bank’s website or in your monthly statement.

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