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IBAN: format, examples, and validation
Read an IBAN by country, verify its MOD-97 checksum, and understand how it differs from a BIC, routing number, and domestic account number.
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In short
What is an IBAN?
An IBAN, or International Bank Account Number, is a country-specific, ISO 13616 account identifier used to automate payment processing. It starts with a two-letter country code and two check digits, followed by that country's fixed-format Basic Bank Account Number. An IBAN identifies one account at one financial institution; it is not itself a payment network.
IBAN anatomy
ISO 13616 gives every IBAN the same high-level envelope, but it does not make domestic account formats identical. SWIFT, the ISO registration authority, publishes the national formats submitted by each country's national standards body or central bank. The BBAN always contains a bank identifier at a country-defined position and may also contain a branch identifier, domestic account number, national check digits, or other national elements.
| Part | Position | Purpose | Example from GB29 NWBK 6016 1331 9268 19 |
|---|---|---|---|
| Country code | 1–2 | ISO 3166-1 country code | GB |
| IBAN check digits | 3–4 | MOD-97-10 integrity check for the complete IBAN | 29 |
| Bank identifier | Country-defined within BBAN | Identifies the financial institution | NWBK |
| Branch identifier | Country-defined, when present | Identifies the branch or routing unit | 601613 |
| Domestic account element | Remainder of the BBAN | Identifies the account under domestic rules | 31926819 |
IBAN formats differ by country
A validator must select the rule for the country code before checking the length and component pattern. Germany and the United Kingdom both use 22 characters but arrange their BBANs differently. France uses 27 and permits an alphanumeric account element. The Netherlands uses 18. The UAE, Saudi Arabia, and Qatar use IBAN outside SEPA, which is a reminder that IBAN and SEPA are not synonyms.
| Country | Length | Registered structure after checks | SWIFT registry example |
|---|---|---|---|
| United Kingdom | 22 | 4 letters bank + 6 digits branch + 8 digits account | GB29 NWBK 6016 1331 9268 19 |
| Germany | 22 | 8 digits bank + 10 digits account | DE89 3704 0044 0532 0130 00 |
| France | 27 | 5 digits bank + 5 digits + 11 alphanumeric + 2 digits | FR14 2004 1010 0505 0001 3M02 606 |
| Netherlands | 18 | 4 letters bank + 10 digits account | NL91 ABNA 0417 1643 00 |
| United Arab Emirates | 23 | 3 digits bank + 16 digits account | AE07 0331 2345 6789 0123 456 |
| Saudi Arabia | 24 | 2 digits bank + 18 alphanumeric account | SA03 8000 0000 6080 1016 7519 |
| Qatar | 29 | 4 letters bank + 21 alphanumeric account | QA58 DOHB 0000 1234 5678 90AB CDEF G |
How the MOD-97 checksum works
The two digits after the country code are calculated with MOD-97-10. To validate, remove spaces, move the first four characters to the end, replace every letter with its numeric value from A=10 through Z=35, and calculate the resulting integer modulo 97. A valid IBAN produces remainder 1. Software should calculate progressively rather than parse the entire value into an ordinary floating-point number.
Worked validation: GB29 NWBK 6016 1331 9268 19
1. Remove spaces
GB29NWBK60161331926819 is the 22-character electronic form published in SWIFT's registry.
2. Move the first four characters
The rearranged value is NWBK60161331926819GB29.
3. Convert letters to numbers
N=23, W=32, B=11, K=20, G=16, and B=11. The numeric string becomes 2332112060161331926819161129.
4. Compute modulo 97
Progressive division gives remainder 1. For an auditable check, the remainders after 6, 12, 18, 24, and 28 numeric digits are 23, 27, 61, 4, and 1.
5. Confirm rather than infer
The checksum passes. That verifies the format and internal check only; it does not query the bank or confirm who owns the account.
What an IBAN validator can and cannot tell you
| Feature | A format validator can check | A format validator cannot establish by itself |
|---|---|---|
| The country code has a registered IBAN format | The recipient controls the account | — |
| The total length matches that country's rule | The account is open or unrestricted | — |
| Letters and digits appear in permitted positions | The bank accepts the intended currency or payment type | — |
| The MOD-97 result is valid | The beneficiary name matches bank records | — |
| The embedded bank or branch pattern is plausible | The payment will clear compliance and reach on time | — |
IBAN versus SWIFT/BIC versus routing number
| Identifier | Identifies | Typical role |
|---|---|---|
| IBAN | One account at a financial institution in an IBAN country | Machine-readable account identification for domestic or cross-border processing |
| BIC/SWIFT code | A business party, commonly a financial institution or branch | Addressing and routing financial messages |
| ABA routing number | A U.S. financial institution | Domestic checks and electronic payment processing in the United States |
| Domestic account number | A customer's account under local bank rules | Pairs with the relevant bank or branch identifier |
A payment form may ask for both IBAN and BIC because they answer different questions: which account, and which institution or message destination. In parts of Europe, “IBAN Only” rules allow the paying institution to derive the BIC for covered payments. That does not mean a BIC is obsolete everywhere or that every international wire can be sent with only an IBAN.
Why the United States does not use IBAN
The United States has not registered a national IBAN format in SWIFT's June 2026 registry. U.S. domestic payments instead use identifiers such as the nine-digit ABA routing number together with an account number. An international payment into a U.S. account may additionally require the receiving bank's BIC, correspondent instructions, address, and purpose information, depending on the sending institution and currency.
Do not invent a U.S. IBAN by adding “US” to a routing and account number. It will not match a registered national format. Ask the receiving bank for its exact incoming international-wire instructions, and use a routing-number directory only for the domestic institution identifier it is designed to verify.
Common IBAN mistakes
- Using the spaced print form in a field that expects the continuous electronic form.
- Confusing the letter O with zero or the letter I with one when copying from an image.
- Validating the checksum but failing to match the beneficiary name and bank instructions.
- Assuming every country has the same length, or padding a shorter national format with zeros.
- Treating any IBAN as a SEPA destination even though SWIFT's registry includes non-SEPA countries.
- Sending the wrong currency because the account identifier looks valid.
- Reusing old instructions after the beneficiary has changed bank, branch, or account.
Frequently asked questions
Frequently asked questions
How many digits are in an IBAN?
There is no universal total. An IBAN has up to 34 alphanumeric characters, but each country has a fixed registered length. For example, the Netherlands uses 18, Germany and the UK use 22, and Qatar uses 29.
Are spaces part of an IBAN?
No. Spaces group the print format for readability. Payment systems normally use the continuous electronic form, so remove spaces without changing any letter or digit.
Does a valid checksum mean the account exists?
No. It means the characters are consistent with the country format and MOD-97 check. Existence, ownership, status, currency support, and beneficiary-name matching require additional bank data.
Is IBAN the same as a SWIFT code?
No. An IBAN identifies an account. A BIC, often called a SWIFT code, identifies a business party used in financial messaging. A transfer form may request both.
Can I calculate an IBAN from an account number?
Not safely without the country's full BBAN rules and the correct bank and branch identifiers. Obtain the IBAN from the account-holding bank rather than constructing payment instructions yourself.
Do all European countries use IBAN?
Many do, but the authoritative question is whether the country has a format in SWIFT's current ISO 13616 registry. Europe, IBAN, and SEPA are overlapping concepts, not identical lists.
What should I enter for a U.S. IBAN?
Nothing fabricated. The United States has no national format in SWIFT's June 2026 registry. Ask the U.S. bank for its account number, routing number, BIC, and any correspondent instructions required for that transfer.
Sources
External links open in a new tab.
- IBAN Registry, release 102 — SWIFT
- International Bank Account Number — SWIFT
- IBAN Plus FAQ and MOD-97 reference — SWIFT
- What is BIC? — ISO Technical Committee 68
- Primary ABA Number — Federal Reserve Board
- Regulation (EU) No 260/2012 — EUR-Lex
- Wire transfer FAQs — Chase
- Foreign currency incoming wire instructions — Wells Fargo
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Glide Research
Payments research
Glide Research maps payment rails, FX corridors, and banking access so travellers, freelancers, and treasury teams can move money without legacy wire tax.
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IBAN: format, examples, and validation
Read an IBAN by country, verify its MOD-97 checksum, and understand how it differs from a BIC, routing number, and domestic account number.
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