What is IBAN (international bank account number)?

The standard account identifier used for bank transfers across Europe and many other countries, made up of a country code, check digits, and the domestic account number.

Exchanges match the name on the sending account to the name on your verified profile, so a transfer from a third party is usually returned or frozen. That name check is the single most common reason a first deposit fails, and it catches joint accounts, business accounts, and accounts held under a maiden name just as readily as an actual third-party payment.

The format is defined by ISO 13616, and the account number it carries is the same one your bank has always used. The country code and check digits are what let a system validate the number before sending anything.

How it works

An IBAN begins with a two-letter country code, then two check digits, then the domestic account identifier. Length is fixed per country and varies between them, up to a maximum of 34 characters under the standard.

The check digits are the useful part. They are computed under the ISO 7064 MOD 97-10 scheme: move the first four characters to the end, convert letters to numbers, and take the whole value modulo 97. A valid IBAN gives a remainder of 1. Any single mistyped character almost always breaks that, which is why a payment interface can reject a bad number instantly rather than sending money to nowhere.

For exchanges, the IBAN sits inside a wider set of controls. Transfers within the Single Euro Payments Area settle under SEPA scheme rules, and payment service providers have been required to verify that a payee's name matches the IBAN before the payer confirms. Firms handling crypto also apply travel rule obligations, so the identity data attached to a transfer matters to them independently of the bank's own checks.

Practical detail worth knowing: exchanges often issue you a dedicated deposit IBAN, sometimes at a partner institution in a different country from your own. That is normal, and it is also why a reference code in the payment description is frequently required for the credit to be matched to your account.

Example

Illustrative walkthrough. You send EUR 1,000 to an exchange's deposit IBAN from a joint account held with your partner, whose name appears first. The exchange's compliance check compares the sending name to your verified profile, finds a mismatch, and holds the deposit. Getting it released usually means providing a bank statement showing the account is yours, and the funds may instead be returned to source, which can take several business days and cost a returned-payment fee at your bank.

Why it matters when you buy

Bank transfer is normally the cheapest funding route and the slowest, while card funding is instant and carries a markup that a published trading fee schedule may not include. The fee comparison shows the all-in cost by payment method, and credit card versus bank transfer compares the two directly. Availability of local transfer rails also varies by country on the jurisdiction pages.

Related terms

• sepa: the euro transfer scheme most IBANs use
• wire transfer: the higher-cost international alternative
• fiat gateway: the rail connecting a bank to an exchange
• minimum deposit: the floor below which transfers are rejected
• travel rule: identity data attached to transfers
• kyc: the verified profile the name is checked against

Questions

Why was my bank transfer returned?

Most often a name mismatch between the sending account and your verified profile, or a missing payment reference. Both are compliance checks rather than banking errors.

Why is my deposit IBAN in another country?

Exchanges hold client money at partner banks, which are frequently in a different jurisdiction from the customer. Within the euro area a cross-border transfer costs the same as a domestic one.

Can I withdraw to a different account than I deposited from?

Usually not without additional verification. Most venues require the withdrawal account to be in your name and many require it to be one you have already used for a deposit.