How an IBAN is structured
Every IBAN has the same three-part anatomy, defined by the ISO 13616 standard:
- 🌍 Country code (2 letters) — e.g. DE for Germany, FR for France, ES for Spain.
- 🔢 Check digits (2 numbers) — calculated from the rest of the IBAN; they catch typos before money moves.
- 🏦 BBAN — Basic Bank Account Number (up to 30 characters) — the national part: bank code, branch code and account number, in whatever format that country uses.
On paper IBANs are printed in groups of four characters for readability (DE89 3704 0044 0532 0130 00), but in online forms you enter them as one continuous string without spaces.
IBAN lengths by country
Length is fixed per country — a German IBAN is always 22 characters, never 21 or 23:
| Country | Code | Length | Example format |
|---|---|---|---|
| Germany | DE | 22 | DE89 3704 0044 0532 0130 00 |
| France | FR | 27 | FR76 3000 4028 3798 7654 3210 985 |
| Spain | ES | 24 | ES91 2100 0418 4502 0005 1332 |
| Italy | IT | 27 | IT60 X054 2811 1010 0000 0123 456 |
| Netherlands | NL | 18 | NL91 ABNA 0417 1643 00 |
| Belgium | BE | 16 | BE71 0961 2345 6789 |
The MOD-97 check: how typos get caught
The two check digits aren't random — they're the result of a MOD-97 calculation (ISO 7064). To verify an IBAN: move the first four characters to the end, convert letters to numbers (A=10, B=11 … Z=35), and divide by 97. If the remainder is 1, the IBAN is structurally valid. This catches nearly all transcription errors — swapped digits, wrong country codes, missing characters — before a payment is ever sent. Note it proves the format is valid, not that the account actually exists.
IBAN and SEPA
Inside the SEPA zone (36 European countries), the IBAN is all you need for euro transfers — payments are processed like domestic ones, usually arriving within one business day, or in seconds with SEPA Instant. Outside SEPA, banks typically also require the BIC/SWIFT code to route the payment. If you deal with European invoices or salaries, you'll meet the IBAN constantly — it's worth knowing how to read one.
❓ IBAN FAQs
How long is an IBAN?
Up to 34 characters. The exact length is fixed per country: Germany 22, France 27, Spain 24, Italy 27, Netherlands 18, Belgium 16.
Is an IBAN the same as an account number?
No. Your national account number sits inside the IBAN, but the IBAN adds a country code and check digits so it works across borders.
Do I still need a BIC/SWIFT code with an IBAN?
Inside SEPA, the IBAN alone is usually enough. Outside SEPA, banks generally still ask for the BIC to route the payment.
Is it safe to share my IBAN?
Yes, for receiving money — an IBAN alone can't be used to withdraw funds. Never share it alongside passwords or one-time codes.
Related: What Is SEPA? · What Is Exchange Rate Markup? · Free IBAN Validator