How to find and correctly use your bank's routing number

If receiving a transfer to a U.S. bank account, or setting one up to send money, the right code will be needed. Here’s what it identifies, and exactly where to find it.

What is a routing number?

A routing number is a nine-digit code that identifies a specific bank or credit union within the United States. Also called an ABA number⁠(opens in new window), the same underlying identifier, it works alongside an account number to direct deposits, direct debits, and transfers to the correct financial institution before the money reaches a specific account. The system dates back to 1910, when it was introduced to sort and route paper checks between banks, and it has since carried over into ACH transfers, wire transfers, and direct deposits without needing to be redesigned.

Where to find and confirm RTN

The most common places to look are a paper check, a banking app, or a bank’s official website. Remitly’s own guide walks through each of these in detail⁠(opens in new window), including what to check if a bank uses more than one code for different transaction types. If instead a specific recipient’s bank is what needs looking up, rather than your own account, Remitly’s bank directory⁠(opens in new window) lists codes by institution name.

Common mistakes

• Using the wrong code for the type of transfer. If a bank has separate numbers for ACH and wire transfers, using the wrong one can delay or misdirect a payment.

• Confusing this with an account number⁠(opens in new window). These are two distinct identifiers with different purposes, both required to complete most transfers.

• Assuming the format works internationally. This system is specific to U.S. banks and isn’t used to identify banks in most other countries.

Why it matters for international money transfers

For anyone sending money to a bank account in the United States, this code is one of the essential pieces of information needed alongside the account number. Getting it right matters because an incorrect entry can send a payment to the wrong bank entirely, not just the wrong account.

For anyone receiving an international transfer into a U.S. bank account, both pieces of information typically need to be provided to the sender or to money transfer provider. Since some banks maintain separate codes for ACH transfers⁠(opens in new window) and wire transfers, confirming which one applies to an international transfer can help avoid an unnecessary delay.

Outside the United States, this system doesn’t apply the same way. Other countries use different formats to identify banks and accounts, such as an IBAN⁠(opens in new window) across much of Europe, or a sort code⁠(opens in new window) in the U.K. and Ireland, so this specific code generally isn’t relevant when sending money to those destinations.

A quick way to sanity-check one

Every valid code passes a specific checksum formula: the nine digits are multiplied in a repeating 3-7-1 pattern and summed, and the result must be a multiple of 10. This is why entering a random nine-digit sequence typically gets flagged as invalid immediately rather than silently accepted, offering a small built-in layer of error catching before a transfer even attempts to process. Passing this check confirms the number is well-formed, though the assigned registry⁠(opens in new window) is what actually confirms which specific bank it belongs to.

Why some banks have more than one

Larger banks sometimes use a different code for different states or for different transaction types, like ACH versus wire transfers. A business checking account can also use a different code than a personal account at the same bank. This is why the number printed on one check isn’t always the correct one for every situation, making it worth confirming exactly which code applies to a wire transfer versus a direct deposit setup.

What happens if the wrong one is used

Using an incorrect code typically causes a transaction to be rejected or delayed rather than silently sent to the wrong bank, since the entry is checked during processing. Still, correcting the error and resubmitting takes time, so verifying it carefully before submitting saves an unnecessary delay. This is a different failure mode than an incorrect account number, which can sometimes still process if the resulting number happens to belong to an active account at the correct bank, making the two types of errors worth checking independently rather than assuming one mistake would catch the other.

In Summary

This nine-digit identifier is a small but essential piece of information that points to a specific bank whenever money moves electronically, whether it’s a domestic paycheck or an international transfer arriving from abroad. Confirming the correct code for a specific transaction type, and pairing it accurately with an account number, helps money land exactly where it should.

This publication is provided for general information purposes only and is not intended to cover all aspects of the topics discussed herein. This publication is not a substitute for seeking advice from an applicable specialist or professional. The content in this publication does not constitute legal, tax, or other professional advice from Remitly or any of its affiliates and should not be relied upon as such. While we strive to keep our posts up to date and accurate, we cannot represent, warrant, or otherwise guarantee that the content is accurate, complete, or up to date.