"ABA" stands for the American Bankers Association, the organisation that founded the ABA routing number system in 1910. ABA routing numbers are unique nine-digit codes that financial institutions in the United States use to identify specific banks or credit unions. They're used in financial transactions, such as electronic funds transfers, to ensure that these transactions are sent to the correct institution and branch.

This guide will cover what ABA routing numbers are, how these numbers are used and how people in American can locate theirs.

What's in this article?

• What is an ABA routing number for a bank?
  
• How are ABA routing numbers used?
  
• How Americans can find their routing number
  
• Difference between a routing number and an account number
  
• How Stripe Payments can help
  

What is an ABA routing number for a bank?

In the US, a routing number is a nine-digit code that identifies banks and financial institutions in different monetary transactions. These numbers go by various names – such as routing transit numbers (RTN), ABA routing numbers, check routing numbers, or Fedwire numbers – depending on their use.

Routing numbers are necessary for a wide variety of financial transactions, including direct deposits, bill payments, electronic transfers and cheque processing. The ACH network relies on routing numbers to move funds electronically, while the Federal Reserve uses them to route Fedwire payments.

How are ABA routing numbers used?

According to the ABA, there are approximately 22,000 active routing numbers in the US. A routing number is required only for direct transfers to or from a bank account – not for debit or credit card transactions. ABA routing numbers are used by banks and other financial institutions to process the following types of financial transactions:

• Direct deposits: Employers, government agencies and other entities in the US use ABA routing numbers to send payments, such as salaries, tax refunds or Social Security benefits, directly to individuals' bank accounts.

• Electronic funds transfers (EFTs): Banks use ABA routing numbers to electronically transfer funds between accounts for purposes such as automatic bill or loan payments, or person-to-person (P2P) transfers.

• Electronic transfers: Banks and credit unions in the US use ABA routing numbers to ensure that funds sent via electronic transfer go to the correct institution.

• Cheques: Financial institutions in the US use ABA routing numbers to process cheques and send them to their correct destination. ABA routing numbers are listed on the bottom of all cheques.

• Automated Clearing House (ACH) transactions: ACH payments – which cover a wide range of electronic transactions, including bank debits and credits, business-to-business (B2B) payments and payroll processing – also require ABA routing numbers.

How to find your routing number

If someone in the US has multiple accounts with a single bank, they might all use the same routing number. But if they have accounts at different banks or different branches, the routing numbers could vary.

Here are a few places where the routing number can be found:

• Online bank portal: Log in to your bank's website and navigate to your account details or payment settings. The routing number is often listed alongside your account number.

• Mobile banking app: Most banking apps display your routing number within the account information section. Look for tabs labelled "Account Details" or "Routing Information".

• Bank statements: Many banks also include the routing number on your monthly bank statements. It might be located in the upper right corner or in your account information details.

• Cheques: The routing number is a nine-digit number printed on the bottom left corner of your cheques. It'll be the first set of numbers you see, followed by your account number and the cheque number.

• Customer service: Customer service representatives can provide this information over the phone or through secure online chat.

• Local bank branch: A bank clerk can also assist with finding your routing number if you prefer in-person service.

• Bank website: Many banks list their routing numbers on their website. Search for "routing number" along with your bank's name to find the relevant page.

Difference between a routing number and an account number in the United States

Routing number

Unlike an account number, which identifies an individual's bank account, an ABA routing number identifies a specific financial institution or bank branch. It directs financial transactions to the correct bank during processing. Routing numbers can change due to branch closures, bank mergers or operational restructuring. A single bank can have multiple routing numbers, depending on its size, location and specific services.

• Structure: A nine-digit code used in the United States.

• Usage: Identifies your bank and is used for direct deposits, electronic transfers, electronic funds transfers and cheque processing.

• Location: Found at the bottom left corner of a cheque, included on bank statements, and provided through the bank's online portal or mobile app. This number is publicly available.

Account number

A bank account number identifies an individual account within a financial institution. It's unique to each account within a bank or credit union. Together with the routing number, it ensures that funds are directed to or from the correct account during electronic transactions. The account number should be shared only when necessary and through secure means.

• Structure: Varies in length and format but is usually longer than a routing number (8–12 digits).

• Usage: Identifies your specific account during a transaction. It's needed for direct deposits, electronic funds transfers, electronic transfers and other banking operations.

• Location: Found on cheques, bank statements and other bank-related documents. On a cheque, it's located between the routing number and the cheque number, and is often separated from the routing number by a space or a symbol.

How Stripe Payments can help

Stripe Payments provides a unified, global payments solution that helps any business – from scaling startups to global enterprises – accept payments online, in person, and around the world.

Stripe Payments can help you:

• Optimise your checkout experience: Create a frictionless customer experience and save thousands of engineering hours with pre-built payment UIs and access to 100+ payment methods, including those that require ABA routing numbers. From electronic transfers to ACH Direct Debits, integration is simple.
  
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• Improve payments performance: Increase revenue with a range of customisable, easy-to-configure payment tools, including no-code fraud protection and advanced capabilities to improve authorisation rates.
  
• Move faster with a flexible, reliable platform for growth: Build on a platform designed to scale with you, with 99.999% uptime and industry-leading reliability.
  

Learn more about how Stripe Payments can power your online and in-person payments, or get started today.