What is an ABA number? ABA routing number explained

You've probably seen the term ABA number on a banking form and wondered if it's the same as a routing number. It is — but knowing a bit more about what that means can help you fill out forms correctly and avoid payment errors.

Whether you're setting up a direct deposit or sending money to a friend, understanding what an ABA routing number is can help you manage your finances better. In this guide, we break down everything you need to know so that you can send and receive money with ease.

What is an ABA routing number?

An ABA routing number is a 9-digit code used to identify a specific financial institution within the US. Think of it as a digital address for your provider. When someone sends money to your account, the routing number tells the financial system exactly which building the money needs to go to, while your account number tells them which room to leave it in.

These numbers are used for several types of transactions, including:

• electronic funds transfers (EFTs)
• Automated Clearing House (ACH) payments
• direct deposits for salaries or government welfare
• paper check processing
• online bill payments
• wire transfers

Without this number, the US banking network wouldn't be able to sort the millions of daily transactions that move between different banks and credit unions.

A brief history of the American Bankers Association number

The routing number system was created by the American Bankers Association (ABA) in 1910. Before this, processing paper checks was a complicated and manual task. Banks needed a way to identify each other quickly to ensure that money was being moved from the correct accounts.

The system was originally designed to make check sorting more efficient. Over the decades, it's evolved to support the digital age. Today, that same 9-digit structure handles everything from the physical checks you write to the real-time digital transfers you make from your phone.

How to find your ABA routing number

If you need to find your ABA routing number, there are several places you can look. Let's break it down:

• On your checks: If you have a paper checkbook, look at the bottom left-hand corner. You'll see 3 sets of numbers. The first 9-digit set is your ABA routing number. It is usually printed in Magnetic Ink Character Recognition (MICR) font, which allows machines to read the numbers quickly.
• In the Revolut app: We make it easy for you to find your details. Simply open your app, tap on your account balance, and your routing and account numbers will be displayed clearly.
• On your bank statement: Most monthly statements will list your account details, including the routing number, near the top of the page.
• Through online banking: If you log in to your bank’s website, you can usually find this information under "Account Details" or "Direct Deposit Information".

How a bank routing number works

The 9 digits in an ABA number are not random. Each section of the code provides specific information to the financial system to ensure the payment is routed correctly.

The 9-digit breakdown:

• Digits 1–4: These represent the Federal Reserve district where the bank is located and the specific processing center originally assigned to the bank.
• Digits 5–8: These identify the specific bank or financial institution.
• Digit 9: This is known as a checksum. It's a digit calculated using a complex mathematical formula based on the first 8 digits. If the final digit doesn't match the result of the formula, the system knows there's an error in the number and will flag the transaction for manual review.

This structure is a safeguard that prevents simple typing errors from sending your money to the wrong provider.

ABA vs routing number: Is there a difference?

The short answer is no. In almost every context, ABA number and routing number are used interchangeably. They both refer to the same 9-digit code.

The term ABA number is simply a more specific name that credits the American Bankers Association for creating the system. You might also hear it called a routing transit number (RTN). Regardless of the name used on your paperwork, you're looking for that same 9-digit sequence.

Routing number vs account number

It's important not to confuse your routing number with your account number. While they often appear next to each other on checks and in apps, they serve very different purposes.

Routing number: Identifies the bank. Many customers at the same bank will have the same routing number.

Account number: Identifies your specific account within that bank. This is unique to you.

When you send money within the US, you'll always need both pieces of information to ensure the money reaches the correct person.

When do you need to use an ABA number?

You'll be asked for your ABA routing number whenever you need to move money electronically between 2 different financial institutions.

Here are some examples:

• Setting up payroll: When you start a new job, your employer will ask for your routing and account numbers so they can send your salary directly to your account.
• Paying bills: If you set up an automatic payment for your electricity or rent, the service provider will need your ABA number to pull the money from your bank.
• Receiving a tax refund: The IRS needs your routing number to deposit your refund directly into your account, which is much faster than waiting for a paper check in the mail.
• Linking payment apps: When you connect your bank account to apps like PayPal or Venmo, you'll need to provide your routing details.

To learn more about sending money, check out our guide to ACH transfers.

Can a bank have more than one ABA routing number?

Yes. It's quite common for larger banks to have multiple routing numbers. This can happen for several reasons.

Firstly, geography plays a role. A bank that operates in multiple states might have a different routing number for its New York branch than it does for its California branch.

Secondly, the type of transaction matters. Some banks use one ABA number for ACH transfers and a completely different one for wire transfers.

Before you initiate a payment, we recommend checking that you have the correct routing number for that specific transaction type. Using an ACH routing number for a wire transfer can lead to the payment being rejected.

ABA vs SWIFT codes

If you're sending money to someone outside the United States, an ABA number is usually not enough. While the ABA system is the standard for domestic transfers within the US, international transfers typically use the Society for Worldwide Interbank Financial Telecommunication (SWIFT) network. To put it simply:

ABA numbers: Used for domestic US transfers.

SWIFT codes: Used for international transfers.

Want to learn more about sending money abroad? Read our guide to international transfers. Our app will also guide you through exactly which details you need.

How to start using Revolut

Whether you're looking for a clear way to track your spending or a fast way to send money to family, we're here to help. Here's how you can sign up for Revolut and get your own ABA routing number:

1. Download the app: Find us on the App Store or Google Play Store and download the app to your phone.
2. Sign up for Revolut: Follow the prompts to create your account. You'll need to provide your basic details and verify your identity with a photo of your ID and a quick selfie.
3. Add money: Once your account's open, you can add money using a debit card, a transfer from another bank, or via Apple Pay or Google Pay.
4. Find your details: To see your ABA routing number and account number, tap on Details, below your balance on the home screen. You can use this information to set up a direct deposit right away.
5. Start spending: You can create a virtual card for online shopping immediately, and order a physical card to be delivered to your door.

Exchange and global transfer fees, fair usage limits, and Terms and Conditions apply.