What Is an IBAN and How It Works

What Is an IBAN?

An IBAN, or International Bank Account Number, is a standardised way to identify a bank account across borders. It was created to make international and cross-border payments faster, cheaper, and less error-prone by giving every account a single, machine-readable identifier that banks in different countries can process automatically.

Despite the word "international" in its name, an IBAN does not replace your regular account number. Instead, it wraps your existing account details inside a longer code that also tells the receiving bank which country and which institution the account belongs to. This lets payment systems validate the number before any money moves.

IBANs are used in more than 80 countries, including all of the European Economic Area, much of the Middle East, and parts of the Caribbean. The United States and Canada, notably, do not use IBANs and rely on routing numbers and account numbers instead.

The Structure of an IBAN

Every IBAN follows the same fixed pattern, though its total length varies by country (from 15 to 34 characters). It always contains three parts, in this order:

1. Country code — two letters identifying the country (for example, DE for Germany, FR for France, GB for the United Kingdom).
2. Check digits — two numbers used to validate the whole IBAN mathematically.
3. BBAN (Basic Bank Account Number) — the country-specific part that identifies the bank, branch, and account.

A Worked Example

Consider this German IBAN:

`` DE89 3704 0044 0532 0130 00 ``

Breaking it down:

• DE — the country code for Germany
• 89 — the check digits
• 37040044 — the bank code (identifies the institution)
• 0532013000 — the account number

The spaces are only for readability. When you enter an IBAN into a payment form or store it in a system, you write it as one continuous string: DE89370400440532013000.

A French IBAN would look different in length and layout, because the BBAN also encodes a branch code and a national check key, but the country code and check digits always come first.

How Check Digits Work

The two digits after the country code are not random. They are calculated using the MOD-97 algorithm defined in the ISO 7064 standard. When a bank or payment app receives an IBAN, it can rearrange and convert the number and check whether the result divides cleanly by 97. If it does not, the IBAN contains a typo.

This built-in validation is one of the biggest advantages of the IBAN system. A single mistyped digit will almost always fail the check before the payment is submitted, catching errors that could otherwise send money to the wrong account.

Check digits confirm that a number is well-formed. They do not confirm that the account exists or that the name matches the holder, which is why many banks now add a separate "Confirmation of Payee" name-check step.

IBAN vs Account Number vs SWIFT-BIC

These three terms are often confused, but they do different jobs:

• Account number — identifies your account within your bank. It is only meaningful in a domestic context.
• IBAN — a superset that includes your account number plus the country and bank identifiers, formatted for cross-border use.
• SWIFT-BIC — the Bank Identifier Code identifies the bank itself on the global SWIFT network. It is 8 or 11 characters (for example, DEUTDEFF).

Think of it this way: the SWIFT-BIC routes a payment to the correct bank, and the IBAN pinpoints the exact account inside that bank. For many international transfers, especially outside the SEPA zone, you need both.

When Is an IBAN Used?

You will typically need an IBAN in these situations:

• SEPA transfers — within the Single Euro Payments Area, IBANs are the standard for euro transfers between member countries. Most SEPA credit transfers require only the IBAN, not the SWIFT-BIC.
• Cross-border transfers outside SEPA — sending money to or from IBAN countries usually requires both the IBAN and the SWIFT-BIC.
• Receiving international salary or invoice payments — you give the sender your IBAN so they can pay your account directly.
• Setting up direct debits in the SEPA zone, such as recurring subscriptions or utility bills.

For everyday domestic payments in some countries you may still use a local account and sort-code format, but the IBAN increasingly appears on statements and cards as the default identifier.

Practical Tips

• Always copy and paste an IBAN when you can, rather than typing it, to avoid transposition errors.
• Double-check the country code first — a wrong country prefix is a common mistake.
• Keep your own IBAN handy; you can usually find it in your banking app, on statements, or by logging into online banking.
• If a transfer is rejected, the check digits are the first thing to verify.

Before opening a new account to receive international payments, it is worth understanding the wider process — see our guide on how to open a bank account online.

FAQ

Is an IBAN the same as my account number?

No. An IBAN contains your account number but adds a country code, check digits, and bank identifier so the account can be recognised internationally.

Do I still need a SWIFT-BIC if I have an IBAN?

For most SEPA euro transfers, the IBAN alone is enough. For transfers outside the SEPA zone, you usually need both the IBAN and the SWIFT-BIC.

Can an IBAN reveal my bank balance or personal details?

No. An IBAN identifies the account for routing purposes only. It does not expose your balance, transactions, or personal information. Still, treat it as you would any account detail and share it only with parties you trust.

What happens if I enter an IBAN with a typo?

The MOD-97 check digits will almost always catch a single-digit error and reject the IBAN before the payment is sent, which is exactly what the validation is designed to do.