IBAN validator online: check any IBAN before you send

Validate any International Bank Account Number instantly with the IBAN validator at ToolHQ. The tool checks the country code, check digits, length, and account number format against ISO 13616 standards. Validated in your browser, no IBAN is sent to any server.

An IBAN, or International Bank Account Number, is a standardised format for bank account numbers used in cross-border payments. Defined by ISO 13616, it allows payment systems across different countries to identify bank accounts unambiguously. A single typo in an IBAN can cause a payment to fail, be returned, or, in some cases, be routed to the wrong account. Validating an IBAN before sending money takes seconds and prevents costly, time-consuming transfer errors.

Key Takeaways

• IBAN is a standardised bank account number format used in international payments, defined by ISO 13616
• Validation checks: country code, MOD-97 check digits, length per country, and BBAN structure
• Each country has a fixed IBAN length: Germany is 22 characters, UK is 22, France is 27
• Validated in your browser, no IBAN is sent to any server
• A single digit error causes failed or misdirected payments: always validate before sending

What an IBAN is and how it is structured

An IBAN is a bank account identifier used in international wire transfers, predominantly across Europe and the Middle East. It was designed to replace the confusing variety of domestic bank account formats with a single internationally recognisable structure.

Every IBAN follows the same structure:

• Country code (2 characters): The ISO 3166-1 alpha-2 country code. For example, DE for Germany, GB for the United Kingdom, FR for France.
• Check digits (2 characters): Two numeric digits calculated using the MOD-97 algorithm. They allow any recipient or software to verify that the IBAN has not been mistyped.
• BBAN (Basic Bank Account Number): The country-specific portion of the IBAN, which encodes the bank code, branch code, and account number in a format defined by the national banking authority.

For example, a German IBAN looks like this: DE75 5121 0800 1245 1261 99

• DE = Germany
• 75 = check digits
• 512108001245126199 = BBAN (bank code + account number)

The total length of an IBAN varies by country, from 15 characters (Norway) to 34 characters (Malta). There is no universal fixed length.

IBAN lengths by country

This table covers the most commonly encountered IBANs. The full ISO 13616 register covers over 80 countries. If you are validating an IBAN from a country not in the table, use the ToolHQ IBAN validator which checks the complete register.

How IBAN validation works

IBAN validation runs through several sequential checks. Each one can catch a different type of error.

Step 1: Country code check The first two characters must be a valid ISO 3166-1 country code that belongs to a country participating in the IBAN system. An IBAN starting with XX would fail immediately.

Step 2: Length check Each country defines a fixed IBAN length. Germany requires exactly 22 characters; France requires exactly 27. An IBAN that is too short or too long is invalid regardless of what the other characters look like.

Step 3: MOD-97 check digit verification This is the primary integrity check. The MOD-97 algorithm works as follows:

1. Move the first 4 characters (country code and check digits) to the end of the string
2. Replace each letter with two digits: A = 10, B = 11, ... Z = 35
3. Divide the resulting number by 97
4. If the remainder is exactly 1, the IBAN is valid

A single transposed digit or mistyped character almost always produces a remainder other than 1, catching the error. This is why the check digits are so effective at catching manual entry mistakes.

Step 4: BBAN structure check The BBAN portion must follow the specific format for its country. Some countries require all digits; others allow alphanumeric characters at specific positions. Many countries also apply their own national checksum to the account number portion.

Mini-story: A freelance designer in the UK was invoicing an international client for the first time. The client's accounts team sent her the IBAN for their German bank account. She copied it from the email into the ToolHQ IBAN validator before submitting the payment. The validator flagged the IBAN as the wrong length: the email had accidentally dropped two characters during formatting. She replied to the client to confirm the correct IBAN and avoided what would have been a returned international wire with the associated fees and delay.

When to validate an IBAN

Before sending an international wire transfer. This is the most important use case. International transfers are not instant and reversal is not guaranteed. Validating the IBAN before submitting to your bank or payment provider catches typos before they cost you time and money.

When receiving a payment instruction. If a supplier, employee, or contractor sends you their bank details, validating the IBAN confirms the number is at least structurally correct before you save it to your payment system.

When building payment systems. Developers and fintech teams use IBAN validation as a form validation step before submitting payment data to a bank API or processing pipeline. Validating at point of entry prevents downstream failures.

When reconciling payment data. Finance teams working through spreadsheets of beneficiary data can batch-validate IBANs to identify suspect entries before scheduling payment runs.

Mini-story: A UK startup's finance team was onboarding a new ERP system and needed to migrate beneficiary bank details from a spreadsheet into the new platform. Before importing, they validated each IBAN individually using ToolHQ. Three of 47 IBANs failed validation: two had been entered with spaces in the wrong places (the validator corrects for spaces, so these passed once reformatted) and one had a transposed digit from the original data entry. Fixing those three before import prevented three failed payment attempts on the first payroll run.

Validate IBANs at ToolHQ before your next payment.

How to use the IBAN validator step by step

1. Open the tool. Visit ToolHQ's IBAN validator.
2. Enter the IBAN. Paste or type the IBAN you want to check. Spaces are acceptable: the tool normalises formatting before validating.
3. Validate. Click "Validate" or the tool validates automatically as you type.
4. Read the result. The tool reports whether the IBAN is valid and, if not, what specific check failed. A full pass means the country code, check digits, length, and BBAN structure are all correct.
5. Note the caveat. Format validation confirms the IBAN is structurally valid. It does not confirm that the account exists or belongs to the person you intend to pay. Always verify account ownership separately for large or first-time payments.

Frequently asked questions

Does a valid IBAN mean the account exists? Not necessarily. IBAN validation checks the format, check digits, length, and structure. It confirms the IBAN is theoretically valid for its country. It does not confirm that the specific account number exists at a bank or belongs to any particular person. For high-value payments, confirm account ownership through a separate channel.

Can I enter the IBAN with or without spaces? Yes. IBANs are often displayed in groups of 4 characters for readability, for example DE75 5121 0800. The validator normalises spacing before running checks. You can enter with or without spaces.

Why does my IBAN have a different number of characters than the table shows? You may have an extra space, a missing character, or the IBAN may be from a country not listed in the table above. The full ISO 13616 register covers more than 80 countries with varying lengths. The ToolHQ validator checks the complete register.

Is IBAN the same as SWIFT/BIC? No. An IBAN identifies an individual bank account. A BIC (Bank Identifier Code), also known as a SWIFT code, identifies a bank. International wire transfers typically require both: the BIC to route the payment to the correct bank, and the IBAN to identify the account at that bank.

Are IBANs used in the USA or Canada? No. The United States and Canada do not use the IBAN system for domestic payments. They use routing numbers and account numbers instead. IBANs are used for incoming international wires to US banks but US domestic transfers do not use them.

The short version

An IBAN is a structured international bank account number that includes a country code, two MOD-97 check digits, and a country-specific account number. Every country has a fixed IBAN length, from 15 characters (Norway) to 34 characters (Malta). Validation checks the country code, check digits, length, and BBAN structure against ISO 13616 standards. A structurally valid IBAN almost always goes where it is intended; an invalid IBAN almost always causes a failed or returned transfer. ToolHQ's IBAN validator runs every check in your browser with no IBAN sent to any server.

Validate an IBAN now at ToolHQ.

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