What is an ABA routing number?
An ABA routing number is the nine digit code that identifies the US bank responsible for paying or receiving a payment, used for ACH transfers, Fedwire wires and checks. Together with the account number, it is what a US payer needs to pay a US account. Example (invented, for illustration only): 095012346, where 0950 is the Federal Reserve routing symbol, 1234 the institution identifier and 6 the check digit.
- The American Bankers Association devised the routing number in 1910, and the industry adopted it in 1911.
- A routing number has nine digits: a four digit Federal Reserve routing symbol, a four digit ABA institution identifier and a check digit.
- The Routing Number Administrative Board, created in June 1985, administers the policy, and the current registrar is LexisNexis Risk Solutions.
- The same bank may use different routing numbers for checks and for wires, so take the number for the payment type you need.
How an ABA routing number works
The routing number was devised by the American Bankers Association (ABA) in 1910 and adopted by the industry in 1911. Its main purpose, in the ABA's words, is to identify the bank responsible to pay or give credit. It is used for paper checks and for electronic payments such as ACH and wires.
| Digits | Name | What it tells you |
|---|---|---|
| 1 to 4 | Federal Reserve routing symbol | The first two digits show the category: 01 to 12 for banks, 61 to 72 for electronic transaction identifiers, 80 for traveler's checks |
| 5 to 8 | ABA institution identifier | The institution within that routing symbol |
| 9 | Check digit | Confirms the other eight digits were typed correctly |
Sources: American Bankers Association, Routing number policy and procedures; check digit weights from Wikipedia, Routing transit number. As published on 29 October 2026.
The check digit follows a fixed formula: multiply the digits by 3, 7 and 1 in turn, add the results, and the total must be a multiple of 10. In the invented example 095012346, the weighted sum is 120, so the number passes. About 26,895 routing numbers are active, and the policy allows up to five per institution.
Where a business meets a routing number
A US business prints its routing and account number on invoices so customers can pay by ACH or Fedwire. A company outside the US meets it when a US customer asks for "routing and account number" instead of a SWIFT code, because US accounts payable teams pay US vendors by domestic transfer.
Routing numbers only work for accounts in the United States. A US customer cannot send ACH to a bank in Mexico or Hong Kong; that payment goes by SWIFT. Electronic transaction identifiers, the 61 to 72 range, cannot appear on checks, and traveler's check identifiers cannot be used for wires or ACH.
Before the first payment, a US customer's accounts payable team usually asks for a bank letter or voided check showing the routing number, account number and account name. Have that document ready in your company's registered name, because a mismatch between the invoice name and the account name is one of the first things a payer's bank checks.
Common mistakes with routing numbers
- Using the check routing number for a wire. Some banks publish a separate number for incoming wires. Ask the bank or check its wire instructions.
- Giving a routing number to a payer abroad. A bank outside the US needs the SWIFT code to send an international wire. The routing number alone will not route it.
- Confusing the routing number with the account number. The routing number identifies the bank and is shared by many customers. The account number is yours.
- Accepting changed details by email. Business email compromise often targets routing and account numbers. Nacha reported the FBI's finding of almost $8.5 billion lost to business email compromise in three years.
Related terms and how Helm handles it
The routing number is the US equivalent of a bank code. For cross-border payments the bank is identified by its SWIFT code, and in Europe the account by its IBAN. Our guide to SWIFT, ACH and Fedwire compares the rails that use it.
Helm provides USD account details in your company's own name: a US routing number and account number that receive ACH, Fedwire and SWIFT payments, so US customers can pay you as they pay a US vendor.
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USD, EUR and GBP accounts in your company's name, with a named account manager.
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How many digits is a routing number?
Nine. The first four are the Federal Reserve routing symbol, the next four the ABA institution identifier, and the last is a check digit.
Is a routing number the same as a SWIFT code?
No. A routing number identifies a bank for US domestic payments such as ACH and Fedwire. A SWIFT code identifies a bank in international payments sent over the Swift network.
Can a bank have more than one routing number?
Yes. The ABA policy allows up to five per institution, and many banks have more after mergers. A bank may also use different numbers for checks and wires.
Who issues ABA routing numbers?
The Routing Number Administrative Board administers the ABA's routing number policy, and LexisNexis Risk Solutions acts as registrar, handling applications and the database.
Can I receive money from abroad with a routing number?
Only from payers who can send a US domestic transfer. A payer abroad usually sends an international wire to the bank's SWIFT code and your account number.
References
- American Bankers Association: Routing number policy and procedures
- Wikipedia: Routing transit number (check digit formula and number in use)
- Nacha: FBI's IC3 finds almost $8.5 billion lost to business email compromise in last three years
- Board of Governors of the Federal Reserve System: Fedwire Funds Services
This guide is general information for businesses, not financial, legal or tax advice. Rules, fees and timings were checked against the sources listed on the review date and may change.