Both numbers identify a bank rather than an account, and they work on different networks: the routing number on the systems that move dollars between American banks, the SWIFT code on the messaging network banks use to reach each other across borders. Below are a side-by-side comparison, a made-up routing number decoded and checked digit by digit, a table of which number each common payment needs and the ways scammers exploit both. The international code is covered in depth in SWIFT codes explained, and the wider topic in the money transfer hub.
What is the difference between a routing number and a SWIFT code?
A routing number is a 9-digit US code for domestic payment systems; a SWIFT code is an 8- or 11-character global code for international payment messages.
| ABA routing number | SWIFT code (BIC) | |
|---|---|---|
| Format | 9 digits | 8 or 11 letters and digits |
| Rules set by | American Bankers Association policy | The ISO 9362 standard |
| Issued by | LexisNexis Risk Solutions, ABA's official registrar | SWIFT, as registration authority |
| Identifies | A US institution eligible for a Federal Reserve account | An institution in any country, optionally one office or unit |
| Used for | ACH, Fedwire, checks and instant payments within the US | Cross-border payment messages |
| Built-in error check | Yes, the ninth digit | None |
| How many per bank | Up to 10, more with board approval | Usually one 8-character code, plus any branch codes |
| Where to find it | Bottom left of a check, online banking | The bank's international wire instructions, SWIFT's BIC Search |
Neither number delivers money to you on its own: every payment also needs your account number, and an international wire into the US usually needs the routing number and SWIFT code together. SWIFT connects more than 12,500 institutions in over 200 countries and territories, while ABA counts about 22,000 active routing numbers, and many small US institutions have a routing number but no SWIFT code.
What do the 9 digits of a routing number mean?
Digits 1 to 4 are the Federal Reserve routing symbol, digits 5 to 8 identify the institution, and digit 9 is a check digit.
The ABA devised the system in 1910 and banks adopted it in 1911, to identify the institution responsible for paying a check. The first two digits still show what kind of number it is:
- 01 to 12: banks and similar institutions, by Federal Reserve district, from 01 for Boston to 12 for San Francisco.
- 21 to 32: thrift institutions, the district number plus 20. New assignments stopped in 1985, but many credit unions and savings institutions still use numbers in this range.
- 00: the US government and its agencies.
- 61 to 72: electronic transaction identifiers, issued to processors that handle payments for banks.
- 80: traveler's checks.
The third and fourth digits narrow the Federal Reserve office or territory; the Fed's Key to Routing Numbers, for example, lists 0712 under its Chicago office. ABA policy is explicit that the number identifies the institution responsible for the payment independent of location, so it does not pinpoint your branch.
How does the routing number check digit work?
Multiply the nine digits by the repeating weights 3, 7 and 1, add the results, and a genuine routing number always produces a total ending in zero.
3 × (d1 + d4 + d7) + 7 × (d2 + d5 + d8) + (d3 + d6 + d9) = a multiple of 10
The Federal Reserve Bank of New York announced the check digit's addition to the routing field on checks from July 1, 1978, so that machines could catch a misread digit. The same test works on any routing number you are given today.
Worked example: Testing the made-up routing number 071205342
| Digit | 0 | 7 | 1 | 2 | 0 | 5 | 3 | 4 | 2 |
|---|---|---|---|---|---|---|---|---|---|
| Weight | 3 | 7 | 1 | 3 | 7 | 1 | 3 | 7 | 1 |
| Product | 0 | 49 | 1 | 6 | 0 | 5 | 9 | 28 | 2 |
The products add up to 0 + 49 + 1 + 6 + 0 + 5 + 9 + 28 + 2 = 100, which ends in zero, so the number is well formed. Working forward from the first eight digits gives the same result: 3 × (0 + 2 + 3) + 7 × (7 + 0 + 4) + (1 + 5) = 15 + 77 + 6 = 98, and the next multiple of 10 is 100, so the ninth digit must be 2.
Now mistype it. 072105342, with the second and third digits swapped, totals 98 and fails. 071205324 totals 88 and fails. But 071250342, with the 0 and 5 swapped, totals 130 and passes, because swapping neighbors that differ by exactly 5 shifts the total by a multiple of 10. The number is invented for this example; do not use it for a payment.
That blind spot covers 10 of the 90 possible pairs of unequal neighboring digits, so about one random transposition in nine slips through, while every single wrong digit is caught. A passing check digit therefore means only that a number could exist. Confirm it against the bank's own instructions before relying on it.
Why can a bank's wire routing number differ from its ACH number?
A bank may hold up to 10 routing numbers and may route wires, ACH and checks through different processing points, so each payment type can have its own number.
ABA policy allows a principal-office number plus nine more, and further numbers with the approval of its Routing Number Administrative Board. The policy's own FAQ describes the typical case: paper items processed at head office while electronic transactions go to a service provider in another Federal Reserve district. Mergers add more, because the surviving bank inherits every number of the banks it absorbed and may keep several in use.
The Federal Reserve's E-Payments Routing Directory reflects the split, with separate lists of Fedwire participants and of institutions that receive FedACH payments. In practice:
- For direct deposit, payroll and bill payments, use the number your bank labels for ACH or direct deposit, which is often the one printed on your checks.
- For an incoming domestic or international wire, use the number your bank labels for wires, even if it differs.
- When in doubt, ask the bank or check its website; a number copied from a third-party site may be out of date after a merger.
Which number do you need for each type of payment?
Use the routing number for anything that stays inside the US and a SWIFT code whenever a bank outside the US sends or receives the payment.
| Payment | Routing number | SWIFT code | Also needed |
|---|---|---|---|
| Paycheck or benefits by direct deposit | Yes, your bank's ACH number | No | Account number and type |
| Federal tax refund by direct deposit | Yes | No | Account number, checking or savings |
| Paying a bill from your account by ACH | Yes | No | Account number |
| Sending a domestic wire | Yes, the recipient bank's wire number | No | Recipient's name, address and account number |
| Receiving a domestic wire | Yes, your bank's wire number | No | Your name and account number |
| Instant transfer through FedNow or RTP | Yes | No | Account number |
| Receiving a wire from abroad | Usually, for the final US step | Yes, your bank's or its intermediary's | Account number, name, address, any intermediary details |
| Sending a wire abroad | No | Yes, the recipient bank's | IBAN or local account number, recipient's address |
| Money from abroad through a transfer service that pays out in the US | Often only this, if it pays by ACH | Not if it pays locally | Account number |
Instant payments are compared in FedNow and RTP, and the trade-offs between the two main domestic options in ACH vs wire transfer.
What happens on an incoming international wire to a US bank?
The foreign bank sends the payment over SWIFT to your bank's code or an intermediary's, and the routing number identifies your bank for the final domestic step.
Dollar payments from abroad settle through US correspondent banks. If your bank has its own SWIFT code and correspondent relationships, the sender needs only that code and your account number. If it does not, your bank's instructions name an intermediary bank with its SWIFT code and put your bank's routing number and your account number in the beneficiary fields, sometimes under a heading such as for further credit. One intermediary is normal: by SWIFT's count, 86% of the payments it carries arrive directly or with a single bank in between.
Worked example: Reading a small bank's incoming-wire instructions
A credit union with no SWIFT connection publishes these made-up instructions for a member expecting $5,000 from a client in Germany:
- Intermediary bank: the correspondent's name and 8-character SWIFT code
- Beneficiary bank: the credit union's name and routing number 071205342, the invented number tested above
- Beneficiary: the member's full name, address and account number 4807112390
The client's bank sends the wire to the correspondent, which passes the money on to the credit union over Fedwire or through an account the credit union holds with it. If the client pays with charges shared, and the intermediary takes $15 while the credit union charges $15 for an incoming wire, the member receives $5,000 − $15 − $15 = $4,970. Both fees are assumptions for the arithmetic; real ones vary by bank.
Who pays which fee is explained in international wire transfer fees and arrival times in how long international transfers take, while receiving money from abroad in the US deals with exchange rates and reporting. If a payment starts in another currency, the currency converter shows the mid-market rate to compare against.
Where do you find each number?
Your routing number is printed at the bottom left of your checks and shown in online banking; your bank's SWIFT code is on its international wire instructions.
On a check, the line of magnetic-ink characters starts with the 9-digit routing number, followed by your account number and the check number. ABA offers a free lookup on its routing number site, limited to two searches a day and ten a month, and the Fed's E-Payments Routing Directory lists institutions that take Fedwire or FedACH payments. For the SWIFT code, look on your bank's website for a page about receiving international wires, or ask the bank; SWIFT's free BIC Search confirms a code once you have one. If your bank says it has no SWIFT code, ask for its intermediary instructions rather than hunting for a code online.
How do scammers misuse routing numbers and SWIFT codes?
Fraudsters rarely fake the codes; they supply genuine routing numbers and SWIFT codes for accounts they control, usually while posing as someone you already pay.
- Changed payment instructions. An email that seems to come from a supplier, a landlord or a title company announces new bank details. Reported losses to this kind of business email compromise reached $3.05 billion in 2025, according to the FBI. Call a number you already have before paying, never one in the email.
- Valid is not verified. A passing check digit or a successful BIC lookup proves the bank exists, not who owns the account, which may belong to a money mule.
- Fake proof of payment. A buyer who sends a screenshot of a wire confirmation and asks you to refund an overpayment is running a classic scam; wait until your own bank shows the money as received.
- Your own numbers. Every check you write shows your routing and account numbers, which is enough for someone to attempt an ACH debit. For consumer accounts, Regulation E expects you to report an unauthorized electronic transfer within 60 days after the statement showing it is sent, to limit your liability for later ones.
If money has already gone, call your bank at once to request a recall and file a report at ic3.gov. Money transfer scams covers the next steps, and the money transfer cost calculator helps compare legitimate ways to send money once the details are confirmed.