In U.S. banking, a transit number and a routing number are the same thing: two shorthand names for the nine-digit ABA Routing Transit Number that identifies your bank on checks, direct deposits, and electronic transfers.1American Bankers Association. ABA Routing Number The confusion is worth clearing up because Canadian banking uses “transit number” to mean something else entirely, and because a U.S. form might ask for the same number under any of several labels.
The U.S. Terms All Point to One Number
The American Bankers Association created the routing transit number system to give every U.S. bank and credit union a unique nine-digit identifier. LexisNexis Risk Solutions is the official registrar and maintains a database of roughly 22,000 active routing numbers.1American Bankers Association. ABA Routing Number The number started with check processing but now also directs ACH payments, wire transfers, and other electronic transactions.2Nacha. ACH Operations Bulletin 4-2024 – Importance of Maintaining Up-to-Date Routing Transit Numbers
So when a form asks for any of the following, it’s asking for the same nine digits:
- Routing number
- Transit number
- Routing transit number (RTN)
- ABA number
You don’t need to look up a different code for each label. One number covers them all.
Canadian Transit Numbers Are Not the Same Thing
North of the border, “transit number” has a specific and different meaning. A Canadian transit number is a five-digit code that identifies a particular bank branch, and it’s paired with a separate three-digit institution number that identifies the bank itself.3CIBC. Transit Number, Institution Number and Account Number CIBC’s institution number, for example, is 010, while the transit number changes with the branch.
For electronic transfers inside Canada, the two are combined with a leading zero to form a nine-digit routing number: the zero first, then the three-digit institution number, then the five-digit transit number. A Canadian check showing 12345-678 becomes 067812345 for electronic use.
This distinction matters at the border. A Canadian five-digit transit number won’t fit a U.S. system expecting nine digits, and a U.S. routing number won’t work in a Canadian system that expects a branch transit paired with an institution number. If someone in Canada asks for your transit number, they’re not asking for your U.S. routing number in disguise.
Finding Your U.S. Routing Number
The bottom of every check has a line of numbers printed in magnetic ink, called the MICR (Magnetic Ink Character Recognition) line, which automated sorting equipment reads to process checks at high speed.4Federal Reserve Board. Frequently Asked Questions About Check 21 It carries three pieces of information, usually in this order:
- The routing transit number, framed by distinctive vertical-bar-with-dot symbols that tell scanners where the bank identifier begins and ends
- Your account number
- The check serial number for that particular check4Federal Reserve Board. Frequently Asked Questions About Check 21
No checkbook on hand? You can find the routing number by logging in to your bank’s online portal, checking the mobile app, calling customer service, or looking on the bank’s public website.
One Bank May Use Different Numbers for ACH and Wires
Some banks use a single routing number for every kind of transaction. Others assign separate numbers for ACH transfers and for wire transfers, and the number printed on your checks may be different from either. Using the wrong one can delay a transaction or cause it to fail.
ACH transactions move in batches through the Automated Clearing House network and handle things like direct deposits, bill payments, and recurring transfers. Wire transfers move through Fedwire one at a time and settle faster, usually for a fee. If a form specifies “ACH routing number” or “wire routing number,” check with your bank rather than assuming the number on your checks will work. The originating bank is responsible for verifying the routing number it submits with each ACH transaction, so your bank can confirm the correct one.2Nacha. ACH Operations Bulletin 4-2024 – Importance of Maintaining Up-to-Date Routing Transit Numbers
International Transfers Use a Different System Entirely
A U.S. nine-digit routing number only works for domestic transfers. International wires use a SWIFT/BIC code (Business Identifier Code), an eight-character alphanumeric code assigned under ISO 9362, sometimes extended to eleven characters with a branch code.5SWIFT. Business Identifier Code (BIC) To send money abroad, you’ll typically need the recipient’s SWIFT/BIC, their account number or IBAN, and the bank’s name and address. Sending an international payment with a U.S. routing number instead of a SWIFT code will fail.
What Happens If You Enter the Wrong Number
The consequences depend on the type of transaction and the type of mistake.
If the routing number you enter doesn’t correspond to a valid institution, the payment will usually be rejected and returned. In the ACH system this generates a return code (such as R03, no account found, or R04, invalid account number format), and the funds go back to the sender. Returns can take several business days, and some billers charge a fee for a failed payment.
The worse case is a valid routing number that belongs to the wrong bank. The payment may go through and land in someone else’s account, and recovering it is slow and difficult.
Tax refunds are the version of this problem that catches people most often. If the routing number on your return fails the IRS’s internal validation, the IRS simply mails you a paper check. If it passes validation but the receiving bank rejects the deposit, the IRS reissues the refund once the bank returns the money. The bad outcome is when the wrong number matches someone else’s valid account and the bank accepts the deposit. In that case you have to work directly with the financial institution to get the money back; the IRS cannot force the bank to return it. After two weeks with no resolution, you can file Form 3911 (Taxpayer Statement Regarding Refund) to start a trace. Banks have up to 90 days to respond, and full resolution can take up to 120 days.6Internal Revenue Service. Refund Inquiries 18
If you split a refund across multiple accounts using Form 8888, any account with an invalid routing number has its portion redirected to the last valid account on the form.7Internal Revenue Service. Form 8888 – Allocation of Refund The IRS is not responsible for a lost refund caused by incorrect account information, so verify both your routing and account numbers with your bank before you file.