בודק IBAN

A free IBAN validator that runs in your browser

This IBAN validator checks an International Bank Account Number for correct structure, the right length for its country, and the ISO 7064 mod-97 checksum — the same test banks use to catch a mistyped account before a payment goes out. Paste an IBAN and you get an instant pass or fail with the specific reason, the number neatly grouped in fours, and a full breakdown of its parts.

Unlike many online IBAN checkers that send the number to a server, everything here happens locally in JavaScript. Nothing is uploaded, so you can validate sensitive banking details — your own or a supplier's — without them ever leaving your device. IBAN.com and iBANapi both offer similar validation but transmit your data to their servers with each check, which can be a concern for finance teams handling client banking information.

What the validator actually checks

Validation runs three layers. First the format: an IBAN must begin with a two-letter country code and two check digits, followed only by letters and digits. Next the length, which is fixed per country — Norway uses 15 characters, Germany and the UK 22, France 27, and Malta 31, up to a maximum of 34. Finally the mod-97 checksum: move the first four characters to the end, convert letters to numbers (A=10 … Z=35), and the whole value modulo 97 must equal 1.

Because the check digits are computed from the rest of the number, almost any single typo — a swapped pair of digits, a wrong character, a missing digit — breaks the checksum and is caught here before money moves. The error message tells you which specific check failed so you know exactly what to fix, rather than just getting an unhelpful 'invalid IBAN' message.

See the structure: country, bank, branch and account

Beyond a yes/no answer, the tool parses the IBAN's structure. It separates the country code and check digits from the BBAN and, where the country's layout is known, labels the bank code, branch code and account number. For GB29 NWBK 6016 1331 9268 19 that means bank NWBK, branch (sort code) 601613 and account 31926819 — useful when you're debugging a payment file or building a banking integration and need to confirm each field is correct.

It also shows both the human-friendly grouped form (blocks of four) and the compact electronic form that payment systems expect, so you can copy whichever format you need without manually reformatting it.

Batch checking and a country reference

Need to vet a whole spreadsheet column? The batch mode takes a pasted list and returns a per-row table of valid/invalid plus the detected country, which you can copy back as CSV. And the searchable country reference lists every supported IBAN country with its exact length and a real sample IBAN — handy for confirming what a Spanish or Saudi IBAN should look like before you key one in.

There's also a test-IBAN generator: choose a country and get a structurally valid, checksum-passing IBAN for software testing and form QA. These are clearly fake and must never be used for a real transfer. They pass all three validation checks, which makes them useful for testing IBAN input forms and banking integrations without exposing real account numbers.

How this compares to IBAN.com, iBANapi and other checkers

The most widely used online IBAN validators are IBAN.com and iBANapi. Both work, but both send your IBAN to their server — IBAN.com to run the validation and display bank details from their paid database, iBANapi for its REST API product. For casual use that's fine; for sensitive client data or bulk validation under GDPR, it's a meaningful privacy consideration worth noting.

Wise (formerly TransferWise) includes an IBAN checker in its transfer flow but only as a step in the payment process, not as a standalone tool. Schwifty is a solid JavaScript library for developers building validation into their own code, but it's not a browser app you can just open and use. This tool runs the full validation entirely client-side, with batch mode, a country reference, a test IBAN generator, and structure parsing — all free and without sending anything to a server.

Private, instant and honest about what it can and can't do

This IBAN checker is free, needs no sign-up, and works offline once loaded. It is, by design, a structure and checksum validator — it confirms the IBAN is correctly formed and self-consistent, not that the account exists or who owns it. Only the receiving bank can verify that. That's an honest limitation worth stating: passing validation catches typos before a payment goes out, but it isn't proof of account ownership or activity.

Bookmark it for the next time you need to validate, format, or understand an IBAN without sending banking details to a third-party server. Works on iPhone and Android too — paste an IBAN on your phone and get the same full validation result you'd get on a desktop.

IBAN structure in depth: ISO 13616 and the MOD-97 algorithm

The International Bank Account Number is governed by ISO 13616, maintained by SWIFT. Every IBAN follows the same outer envelope: a 2-letter country code (ISO 3166-1 alpha-2), 2 check digits, and then the BBAN (Basic Bank Account Number) — up to 30 alphanumeric characters whose internal layout is defined independently by each country. Three examples illustrate how much the BBAN format varies: GB29NWBK60161331926819 (United Kingdom, 22 chars) encodes a 4-character bank code followed by a 6-digit sort code and 8-digit account number; DE89370400440532013000 (Germany, 22 chars) embeds an 8-digit Bankleitzahl and a 10-digit Kontonummer; FR7630006000011234567890189 (France, 27 chars) contains a 5-digit bank code, 5-digit branch code, 11-character account number, and a 2-digit national check key.

The MOD-97 check digit algorithm is what makes IBAN self-validating. To verify any IBAN: (1) move the first four characters — the country code and check digits — to the end of the string; (2) replace every letter with its numeric equivalent, where A=10, B=11, and Z=35, treating the resulting string as a single large integer; (3) compute that integer modulo 97. A valid IBAN always produces a remainder of exactly 1. The two check digits embedded in positions 3–4 are chosen when the IBAN is first issued so this identity holds. Because the check covers the entire account string, a single transposed digit almost always breaks the calculation — the false-pass rate for a random wrong character is roughly 1-in-97.

IBAN became mandatory across the SEPA zone (Single Euro Payments Area — 36 countries including all EU member states plus Iceland, Norway, Liechtenstein, Switzerland, Monaco, San Marino, Andorra, Vatican City, and the UK) in February 2016. Before that date, many banks accepted the old domestic account-and-sort-code format for cross-border euro transfers. Today any SEPA Credit Transfer that carries a domestic-format account number is simply rejected at the clearing layer, which is why accurate IBAN validation at data-entry time directly prevents failed payments.

Which countries use IBAN — and the major holdouts

More than 86 countries have officially adopted IBAN. The full list covers every European nation, most of the Middle East (Saudi Arabia, UAE, Kuwait, Qatar, Bahrain, Jordan, Lebanon), a growing number of North African and Sub-Saharan African countries, and several Caribbean and Latin American jurisdictions including Costa Rica, Dominican Republic, and Brazil. Within this group, the format and length differ by country but the outer ISO 13616 envelope is identical, which is why a single validation algorithm works universally.

The significant holdouts are the world's other major banking markets. The United States does not use IBAN; domestic transfers rely on ABA routing transit numbers — 9-digit codes issued by the American Bankers Association since 1910, where the first two digits identify the Federal Reserve district. Canada uses a similar 3-digit institution number plus 5-digit transit number system. Australia routes domestic payments with a BSB (Bank State Branch) code — a 6-digit number structurally similar to the UK sort code — alongside the account number. China, Japan, and India maintain their own domestic schemes (CNAPS, Zengin, and IFSC/NEFT respectively). None of these map onto IBAN, so a US business receiving an EU supplier's IBAN and a German business receiving a US supplier's routing number are dealing with genuinely incompatible systems — there is no conversion between them.

This geographic split has a practical consequence: when paying internationally into the United States, SWIFT/BIC plus the account number is the correct combination to supply, not an IBAN. Conversely, when paying into Germany or France, the IBAN alone is sufficient for SEPA transfers; the BIC is no longer mandatory within SEPA as of November 2016, though many banks still ask for it as a belt-and-suspenders check.

SWIFT/BIC codes and their relationship to IBAN

SWIFT (Society for Worldwide Interbank Financial Telecommunication) is the cooperative messaging network banks use to exchange payment instructions internationally. Founded in 1973 and headquartered in Brussels, it connects more than 11,000 financial institutions in over 200 countries. Every message travelling over SWIFT carries a BIC (Bank Identifier Code) that identifies the sending and receiving institution. A BIC is 8 or 11 characters: a 4-letter bank code, a 2-letter country code, a 2-character location code (which can include a digit), and an optional 3-character branch code. DEUTDEDBFRA, for instance, decodes as Deutsche Bank (DEUT), Germany (DE), Frankfurt office (DB), Frankfurt branch (FRA).

IBAN and BIC solve different problems and operate at different layers. The IBAN identifies the account — it encodes the country, the bank, the branch, and the account number in a single self-checking string. The BIC identifies the bank as an institution within the SWIFT network. Together, they uniquely route a payment: the BIC tells the network which institution to deliver the message to; the IBAN tells that institution which account to credit. For SEPA transfers within Europe, the BIC is no longer required — the IBAN alone is sufficient because the SEPA clearing infrastructure can derive the destination bank from the BBAN. For international transfers outside SEPA — for example from the UK to Australia or from Germany to the United States — both the IBAN (or local account number) and the BIC/SWIFT code are still required.

One common source of confusion is the terms SWIFT code and BIC being used interchangeably. They refer to the same identifier. SWIFT issues and maintains the BIC registry, so SWIFT code is colloquial for BIC. When a payment form asks for a SWIFT/BIC code, a SWIFT code, or simply a BIC, it is asking for the same 8- or 11-character bank identifier. The 11-character version targets a specific branch; the 8-character version (or one ending in XXX) targets the bank's head office, and the head office routes internally to the right branch from there.

Common IBAN errors, validation vs. verification, and virtual IBANs

The most frequent IBAN entry mistakes fall into four categories. Transposed digits — swapping two adjacent digits — are the classic OCR and manual-keying error; the MOD-97 algorithm catches nearly all single transpositions because changing any one character changes the mod-97 remainder away from 1. Wrong country code is surprisingly common when similar two-letter codes are adjacent on a keyboard — GB (United Kingdom) versus GR (Greece), or BE (Belgium) versus BG (Bulgaria) — and the wrong code may produce a valid-length string for a different country, causing the length check to pass but the checksum to fail. Incorrect character count — a missing digit when copying from a bank statement that printed the IBAN across two lines — is caught immediately by the per-country length table. Finally, letter–digit confusion such as a capital O substituted for a zero, or the letter I for the digit 1, produces a format error before any arithmetic is needed. Spaces never matter for validation: GB29 NWBK 6016 1331 9268 19 and GB29NWBK60161331926819 are the same IBAN — this tool normalises them both identically.

It is essential to understand the difference between IBAN validation and IBAN verification. Validation — what this tool performs — is entirely offline: it checks that the string conforms to the ISO 13616 format, that its length matches the country's registered specification, and that the MOD-97 remainder equals 1. A validated IBAN is correctly formed, but it may belong to a closed account, a non-existent account, or simply be a syntactically valid string that was never assigned to anyone. Verification — confirming that the account is real, open, and belongs to a named person — requires contacting the receiving bank or using a paid commercial API such as IBAN.com's verification product or OpenIBAN. Verification inevitably means transmitting the IBAN to a third-party server, which is why this tool deliberately stops at validation: all checks are local, and nothing leaves your device.

Virtual IBANs (vIBANs) are a modern wrinkle worth knowing about. Payment processors such as Stripe, Wise, and Airwallex assign dedicated IBANs to individual customers or invoices; incoming payments to those IBANs are automatically swept into a master pooled account and reconciled by the processor. A vIBAN passes all standard validation checks — it has the correct country format, the right length, and a valid MOD-97 checksum — because it is a fully issued, real IBAN. The difference is operational, not structural: the account behind it is held by the payment processor, not a traditional bank, and the funds are immediately redirected. vIBANs are widely used in B2B payment automation and accounts-receivable workflows; if your IBAN validation passes but a payment still fails, the recipient may have supplied a vIBAN that has been deactivated or that your bank's compliance system has flagged as belonging to a non-bank institution.