IBAN Calculator

What Is an IBAN?

An International Bank Account Number (IBAN) is a standardised code used to identify a specific bank account across international borders. Introduced by the ISO 13616 standard and adopted by SWIFT, the IBAN eliminates ambiguity in cross-border payments by encoding the country, bank, branch, and account number in a single, verifiable string.

Before IBANs, international wire transfers required senders to provide separate national account numbers and routing codes — leading to frequent errors and failed payments. An IBAN bundles all of this information into one self-contained, checksum-verified number, dramatically reducing misdirected transfers.

How IBAN Works — The Structure

Every IBAN follows a consistent four-part structure:

Position	Component	Example (GB)	Description
1–2	Country Code	GB	ISO 3166-1 alpha-2 country code
3–4	Check Digits	29	MOD-97 checksum, computed from the rest
5+	BBAN	NWBK60161331926819	National account number (varies by country)

The BBAN (Basic Bank Account Number) encodes national-specific routing data — bank code, branch code, and account number — in a format defined by each country's banking authority. Its length varies from 11 characters (Norway) to 30 characters (Kuwait).

The MOD-97 Check Digit Algorithm

The two check digits in positions 3–4 are computed using a standardised mathematical algorithm:

1. Rearrange: Move the first 4 characters (country code + "00") to the end of the IBAN.
2. Convert letters to numbers: Replace each letter with its numeric equivalent (A=10, B=11, … Z=35).
3. Compute: Calculate the result modulo 97.
4. Derive check digits: Subtract the result from 98. Pad to 2 digits.

To validate an IBAN, you rearrange the full IBAN (not "00") and verify that the modulo-97 result equals exactly 1. Our validator runs this calculation instantly in your browser.

IBAN Length by Country

IBAN lengths are fixed per country and range from 15 to 34 characters:

Country	Code	IBAN Length	Example
Norway	NO	15	NO93 8601 1117 947
Belgium	BE	16	BE68 5390 0754 7034
Netherlands	NL	18	NL91 ABNA 0417 1643 00
Germany	DE	22	DE89 3704 0044 0532 0130 00
United Kingdom	GB	22	GB29 NWBK 6016 1331 9268 19
UAE	AE	23	AE07 0331 2345 6789 0123 456
Saudi Arabia	SA	24	SA03 8000 0000 6080 1016 7519
France	FR	27	FR76 3000 6000 0112 3456 7890 189
Kuwait	KW	30	KW81 CBKU 0000 0000 0000 1234 5601 01

How to Use the IBAN Calculator

Validate Mode

1. Paste your IBAN into the input field — spaces are stripped automatically.
2. The tool validates in real time using the MOD-97 algorithm.
3. If valid, you see the country, check digits, and BBAN broken down in a colour-coded display.
4. Use the Copy button to copy the clean, space-formatted IBAN.
5. Click "Explain with AI" for a plain-English breakdown of the IBAN structure.

Generate Mode

1. Select your country from the dropdown (20 countries supported).
2. Enter the required bank details — bank code, branch code, account number — as shown on your bank statement.
3. Click "Generate IBAN" — the tool assembles your BBAN and computes the correct check digits automatically.
4. Copy the generated IBAN or switch to Validate mode to confirm it.

Where to Find Your IBAN

Your IBAN appears in several places:

• Bank statement: Usually on the first page, labelled "IBAN" or "Account Number".
• Online banking: In the account details or settings section.
• Bank-issued documents: Cheque books (Germany), RIB documents (France), sort code slips (UK).
• Bank's website: Most banks have an IBAN lookup tool.
• Call your bank: They can provide your IBAN instantly over the phone or secure chat.

Note: Your IBAN is not secret like a password. It is safe to share with employers for salary payments, suppliers for invoices, and overseas contacts for transfers.

IBAN vs Account Number vs SWIFT/BIC

These three identifiers serve different purposes in international banking:

Identifier	What It Is	When You Need It
IBAN	Full bank account in one verifiable string	Sending or receiving international payments
Account Number	Local account number (part of the BBAN)	Domestic transfers only
SWIFT/BIC	Bank identifier code (8 or 11 characters)	Sometimes required alongside IBAN for SWIFT transfers outside SEPA

Within the SEPA zone (36 European countries), IBAN alone is sufficient for euro transfers. Outside SEPA — for example, USD wires to a UK account — both IBAN and BIC may be required.

Benefits of Using IBAN

• Error detection: The MOD-97 checksum catches the vast majority of typos before a transfer is sent.
• Automatic routing: Banks can extract the country, bank code, and branch code directly from the IBAN — no separate routing number needed.
• Global standardisation: Adopted across Europe, the GCC, and beyond, IBAN creates a common language for international payments.
• Faster processing: Straight-through processing (STP) rates are higher for IBAN payments, meaning fewer manual interventions and faster settlement.
• Reduced fees: SEPA credit transfers using IBAN are typically free or very low cost within member countries.

Common IBAN Mistakes and How to Avoid Them

1. Transposing digits — The most common error. Always copy-paste from your bank statement rather than typing manually. Our validator catches this instantly.
2. Wrong country length — Each country has a fixed IBAN length. Entering 21 digits for a German IBAN (which requires 22) will fail validation.
3. Using local account number instead of full IBAN — Your local 8-digit sort code account number is not your IBAN. The IBAN includes the bank and branch codes as a prefix.
4. Confusing IBAN with BIC/SWIFT — IBAN starts with two country letters followed by two digits. BIC starts with the bank's letter code and ends in a country code. They are different identifiers.
5. Not zero-padding shorter account numbers — Germany requires 10-digit account numbers. If your account number is only 8 digits, it must be left-padded with two zeros in the BBAN.
6. Sharing a wrong IBAN — Always verify before sending. A technically valid IBAN (one that passes MOD-97) could still belong to a different person if a digit is transposed into another valid sequence. Confirm the recipient's bank name matches.

Benefits of Using This Tool

• Instant validation — MOD-97 check runs in your browser; no server round-trip, no delay.
• 20 countries — Covers all major European and GCC IBAN formats.
• Two modes — Validate an existing IBAN or generate a new one from bank details.
• AI explanation — Plain-English breakdown of any IBAN's structure, algorithm, and tips.
• No data stored — All computation happens locally in your browser. Your bank details are never sent to a server.
• PDF report — Download a formal IBAN verification report for your records.
• Free, no registration — Unlimited validations and generations at zero cost.