IBAN vs Routing Number — Key Differences & When to Use Each

IBAN vs Routing Number: Quick Summary

IBANs and routing numbers both identify bank accounts for transfers, but they serve different geographic regions and follow different standards. IBANs are used internationally (primarily Europe), while routing numbers are a US-specific system. Here's a quick comparison:

What Is an IBAN?

An IBAN (International Bank Account Number) is a standardized account identifier used in 80+ countries to facilitate cross-border and domestic bank transfers. The IBAN contains the country code, check digits, bank identifier, and account number in one unified format.

Example IBAN (UK):

GB29 NWBK 6016 1331 9268 19
GB ── Country code (Great Britain)
29 ── Check digits
NWBK ── Bank code (NatWest)
6016 13 ── Sort code
3192 6819 ── Account number

IBANs were developed to reduce errors in international transfers by providing a standardized format that can be validated before a payment is sent. The built-in check digits catch typos and formatting mistakes upfront, preventing failed transfers and associated fees.

Generate valid IBANs for testing with Qodex's free IBAN Generator.

What Is a Routing Number?

A routing number (officially called an ABA Routing Transit Number) is a 9-digit code that identifies a specific US bank or credit union. Introduced in 1910 by the American Bankers Association, routing numbers are used for domestic US transactions including ACH transfers, wire transfers, direct deposits, and check processing.

Example routing number:

021000021
021 ── Federal Reserve routing symbol
0000 ── ABA institution identifier
2 ── Check digit
(This is JPMorgan Chase's primary routing number)

Key facts about routing numbers:

• US-only system — routing numbers are not used outside the United States

• Multiple per bank — large banks have different routing numbers for different states or transaction types

• Printed on checks — the first 9 digits at the bottom left of a US check are the routing number

• Separate from account number — unlike IBANs, routing numbers don't contain the account number

Generate valid routing numbers for testing with Qodex's free Routing Number Generator.

Key Differences Between IBAN and Routing Number

1. Geographic Scope

IBANs are used internationally across 80+ countries, primarily in Europe, the Middle East, and parts of Africa. Routing numbers are exclusively a US system. If you're sending money to Europe, you need an IBAN. If you're sending money within the US, you need a routing number.

2. What They Contain

An IBAN is a comprehensive identifier that includes the country code, bank identifier, and account number in a single string. A routing number only identifies the bank — you need to provide the account number separately. This makes IBANs more self-contained but longer.

3. Format and Length

Routing numbers are always exactly 9 digits. IBANs vary from 15 to 34 characters depending on the country and contain both letters and numbers. This standardized but variable format reflects different countries' domestic banking systems.

4. Error Detection

Both systems include check digits for validation. IBANs use a 2-digit check (MOD-97 algorithm) that validates the entire number. Routing numbers use a single check digit (position 9) based on a weighted sum of the first 8 digits. IBAN validation is generally considered more robust.

5. Transaction Types

IBANs are used for SEPA transfers, international wires, and domestic transfers within IBAN countries. Routing numbers are used for ACH transfers, domestic wire transfers, direct deposits, and check clearing within the US.

When to Use an IBAN

You need an IBAN when:

• Sending money to Europe or IBAN countries — mandatory for EU/EEA transfers

• Receiving international payments into an account at an IBAN-country bank

• SEPA payments — IBANs are the standard identifier for Single Euro Payments Area transfers

• Setting up recurring international payments — subscriptions, payroll, or supplier payments to IBAN countries

For transfers to the US, use a routing number instead. For other countries without IBANs (Canada, Australia, etc.), use the SWIFT code plus domestic account details.

When to Use a Routing Number

You need a routing number when:

• Domestic US transfers — ACH payments, direct deposits, and wire transfers between US banks

• Setting up direct deposit — employers need your routing number to deposit your paycheck

• Paying bills online — US bill payment systems require your bank's routing number

• International transfers TO the US — foreign senders need your bank's routing number (plus SWIFT code) to wire money to your US account

Frequently Asked Questions

Can I use an IBAN instead of a routing number in the US?

No. US banks do not use IBANs. The US banking system relies on ABA routing numbers (9-digit codes) to identify banks and separate account numbers to identify accounts. If a foreign bank or payment platform asks for your IBAN and you have a US account, you should provide your routing number and account number instead, along with your bank's SWIFT/BIC code for international transfers.

How do I find my routing number?

You can find your US bank routing number in several places: on your checks (the first 9 digits at the bottom left), in your online banking portal under account details, on your bank's website, or by contacting your bank directly. Note that large banks have different routing numbers for different states, so make sure you use the one associated with your specific account.

Do I need a SWIFT code and an IBAN for international transfers?

For transfers to IBAN countries (most of Europe), you typically need both the recipient's IBAN and their bank's SWIFT code. However, for SEPA transfers within Europe, an IBAN alone is usually sufficient. For transfers to the US, you need the recipient's routing number, account number, and the bank's SWIFT code — no IBAN is involved.

What is the SEPA system and how does it relate to IBANs?

SEPA (Single Euro Payments Area) is a payment integration system that standardizes euro-denominated transfers across 36 European countries. Within SEPA, an IBAN is the only account identifier needed — no SWIFT code required. SEPA payments are typically processed within one business day and often have lower fees than traditional international wire transfers. IBANs are mandatory for all SEPA transactions.

Are routing numbers the same as sort codes?

They serve a similar purpose but are different systems. US routing numbers are 9 digits, while UK sort codes are 6 digits. Both identify a specific bank and branch for domestic transfers. Sort codes are embedded within UK IBANs, while routing numbers are separate from account numbers. Other countries have their own equivalents: Canada uses transit numbers, Australia uses BSB codes, and India uses IFSC codes.

Can a routing number be used for international transfers?

Yes, but only for transfers TO the US. When someone abroad sends money to a US bank account, they need the bank's SWIFT code (for international routing) plus the routing number and account number (for domestic delivery). Routing numbers alone cannot be used for outbound international transfers from the US — those require the recipient's SWIFT code and either an IBAN or local account details.