A guide to routing transit numbers

A guide to Routing Transit Numbers

When you’re transferring money to a US bank account for business or personal reasons, you’ll need a Routing Transit Number (RTN). Find out what routing numbers are used for, what their format is and how to validate one when you’re sending money to an American bank account.

What is a Routing Transit Number?

A Routing Transit Number is a nine-digit number used to identify individual bank branches in the United States of America. Routing Transit Numbers (or American Bankers Association numbers) work similarly to sort codes in the UK. When you send money to the US, you’ll need your recipient’s 17-digit account number as well as a Routing Transit Number.

Informally, a Routing Transit Number is also known as:

  • An American Bankers Association or ABA Number.
  • An ABA RTN number.
  • An ABA routing number.
  • An ABA number
  • An ABA transit number.
  • A check routing number.
  • A routing number.
  • A bank routing number.
  • A local routing number.
  • A Fedwire number.

If your recipient mentions one of the above, they’re probably talking about a Routing Transit Number. Although RTNs are different from IBAN numbers, SWIFT or BIC codes and NUBAN numbers, they do perform similar functions. 

Banking in America

The main banking institution is the Federal Reserve System‍ (or the Federal Reserve) which sets monetary policy and maintains the supply of American dollars in the economy. The Federal Reserve is the American version of the Bank of England in the UK and, as such, doesn’t offer individual bank accounts.

For personal and business accounts in the US, there are popular brands such as Wells Fargo, Bank of America, Capital One and M&T Bank

There are also several international banks in America like HSBC, Credit Suisse and BNP Paribas, with branches across the country.

Did you know? Routing numbers were initially established for checking (current) accounts but have since evolved to include identifying banks during electronic transactions as well.

What is the Routing Transit Number format?

An RTN number consists of 9 numerical digits written without any spaces or dashes. 

An example of a 9-digit RTN is:


All Routing Transit Numbers are comprised of: 

  • The bank’s physical location – the first four digits.
  • The Federal Reserve bank routing the transaction – the next two digits.
  • The Federal Reserve check processing centre for the bank – digit seven.
  • The Federal Reserve district where the bank is based – digit eight.
  • A security number – the last digit.

How to find a Routing Transit Number

Whether you’re sending money to a loved one or making a transfer to your US bank account, you’ll need a routing number. You’ll be able to find your own routing number in your online banking account, a recent bank statement or on a check (cheque). 

If you’re sending money to someone else, you’ll need to ask your recipient for their RTN and account number.

Top tip: A handy place to find your routing number is on your checks (cheques). Your 9-digit RTN is at the bottom next to your 17-digit account number.

Once you have your loved one’s RTN number, it’s a good idea to check it online before transferring money to America

How to validate a routing number

If you need to check if an RTN is valid, bank.codes have this useful routing number validator. Enter your contact’s ABA routing number and get confirmation on its validity from America’s top banks, including Chase, Liberty Bank and The First National Bank

While using routing number validators helps, it’s always a great idea to check the number with your recipient before sending money to a US bank account. An incorrect number could delay or transfer your payment to the wrong bank account. 

Discover a faster, cheaper way to send money to America. Download the Azimo app on iOS or Android and start transferring funds today.