The one-line answer

Being paid from inside the US? Give your routing number and account number. Being paid from another country? Give your bank's SWIFT/BIC code and your account number. Chase puts it this way: "SWIFT codes are required for international transfers, while routing numbers are used for domestic U.S. transactions" (Chase).

Side by side

	Routing number (ABA)	SWIFT/BIC code
What it identifies	A bank or credit union in the US	A bank or other organisation anywhere in the world
Shape	Always 9 digits	8 or 11 letters and digits
Who created it	The American Bankers Association	Registered under ISO 9362, with Swift as registration authority
Used for	Direct deposit, bill pay, transfers and wires inside the US	Wires that cross a border
Example	021000021 (Chase, domestic wires)	CHASUS33 (Chase)

Sources: Chase, Swift FAQ, Chase wire FAQ.

Wells Fargo says the same from the other side: the SWIFT code "is used instead of a routing number for international wire transfers" (Wells Fargo).

Why you cannot swap them

A sender abroad pays through their own bank, which sends a payment message over the Swift network. Swift carries messages, not money: Chase notes that SWIFT "isn't a financial institution and doesn't hold or transfer funds" (Chase). A message has to be addressed to a BIC. A 9-digit routing number does not fit the 8-or-11-character shape, so the sender's bank cannot use it as the address. The format checker shows the shape rule.

In the other direction, a payment between two US banks uses the routing number, as Chase's comparison says.

The wire routing number can differ from the one on your cheques

Bank of America warns that some banks use different routing numbers for wires and for ACH transfers (Bank of America). PNC says incoming wires have a different routing number than the one shown on your account (PNC). Before you give out a number for a wire, use the one your bank labels for wires.

Bank	Routing number the bank gives for wires	SWIFT/BIC for wires from abroad
Chase	021000021	CHASUS33
Bank of America	026009593	BOFAUS3N (US dollars), BOFAUS6S (foreign currency)
Wells Fargo	121000248	WFBIUS6S
PNC	043000096	PNCCUS33

All four read from the banks' own pages on 26 October 2026; links and more banks are on US bank SWIFT codes.

What about IBAN and sort codes?

An IBAN identifies an account. A routing number and a SWIFT code identify a bank. Chase says it does not use IBANs (Chase), so a US account is identified by its account number. If you are paying into Europe, the payee will have an IBAN; see do you need a BIC?.

Common slips

Giving the SWIFT code to a US employer for direct deposit. Payroll needs the routing number.
Giving the routing number to a relative abroad. Their bank needs the SWIFT/BIC.
Using the cheque routing number for an incoming wire at a bank that uses a separate wire number.
Copying a code from an unofficial list. Take it from the bank's site or app, or check it in Swift's own search: finding a SWIFT code.