IBAN Validator
About IBAN
The International Bank Account Number (IBAN) is an international standard for identifying bank accounts across borders. It was originally developed to facilitate payments within the European Union but is now used worldwide.
IBAN Structure:
- Country Code - 2 letters (e.g., GB for United Kingdom)
- Check Digits - 2 digits for validation
- BBAN - Basic Bank Account Number (varies by country, up to 30 characters)
Validation Process:
- Check the IBAN length (15-34 characters)
- Verify the format (2 letters, 2 digits, then alphanumeric)
- Move the first 4 characters to the end
- Convert letters to numbers (A=10, B=11, etc.)
- Calculate mod-97 of the numeric string
- Valid if the result equals 1
Note: This tool only validates the IBAN format and check digits. It does not verify if the account actually exists or is active.
How It Works
The International Bank Account Number (IBAN) is a standardized international numbering system developed by the International Organization for Standardization (ISO) and the European Committee for Banking Standards (ECBS) to facilitate cross-border transactions and reduce transcription errors.
An IBAN has a specific structure: a 2-letter country code (ISO 3166-1 alpha-2), followed by a 2-digit check number, followed by the Basic Bank Account Number (BBAN) which varies in length and format by country. Total length ranges from 15 characters (Norway) to 34 characters (Malta).
Validation uses the mod-97-10 algorithm specified in ISO 7064. The process: move the first 4 characters to the end of the IBAN, replace each letter with its numeric equivalent (A=10, B=11, ..., Z=35), then check if the resulting large integer divided by 97 leaves a remainder of 1. This checksum catches common transcription errors like digit transposition or single-character mistakes. All validation happens in your browser—account numbers never leave your device.
An IBAN has a specific structure: a 2-letter country code (ISO 3166-1 alpha-2), followed by a 2-digit check number, followed by the Basic Bank Account Number (BBAN) which varies in length and format by country. Total length ranges from 15 characters (Norway) to 34 characters (Malta).
Validation uses the mod-97-10 algorithm specified in ISO 7064. The process: move the first 4 characters to the end of the IBAN, replace each letter with its numeric equivalent (A=10, B=11, ..., Z=35), then check if the resulting large integer divided by 97 leaves a remainder of 1. This checksum catches common transcription errors like digit transposition or single-character mistakes. All validation happens in your browser—account numbers never leave your device.
Use Cases
1. Payment Form Validation
E-commerce sites, payment platforms, and banking portals validate IBANs before submitting payment requests to backend systems. Real-time IBAN validation in forms prevents costly payment failures due to typos, saving both processing fees and customer service overhead when transactions fail at the banking level.
2. Batch Payment Processing
Accounts payable departments processing supplier payments or payroll for international staff need to validate IBANs before batch submission. Validating IBANs in advance catches errors before they reach the payment network, where corrections require additional fees and delays of 1-3 business days.
3. Data Quality in Financial Systems
ERP systems, CRM tools, and financial databases storing customer or supplier bank details benefit from IBAN validation at data entry time. Storing invalid IBANs creates problems when payments are eventually processed. Validation at entry time ensures data quality at the source.
4. Educational and Compliance Purposes
Finance professionals, developers building payment systems, and compliance officers learning about international banking standards use IBAN validators to understand the format requirements for different countries. Each country's BBAN format has specific rules that the validator can explain.
5. API Integration Testing
Developers building integrations with banking APIs, SWIFT networks, or payment processors need to test with valid IBAN numbers. Generating and validating test IBANs ensures that integration tests use properly formatted account numbers without requiring real banking credentials.
E-commerce sites, payment platforms, and banking portals validate IBANs before submitting payment requests to backend systems. Real-time IBAN validation in forms prevents costly payment failures due to typos, saving both processing fees and customer service overhead when transactions fail at the banking level.
2. Batch Payment Processing
Accounts payable departments processing supplier payments or payroll for international staff need to validate IBANs before batch submission. Validating IBANs in advance catches errors before they reach the payment network, where corrections require additional fees and delays of 1-3 business days.
3. Data Quality in Financial Systems
ERP systems, CRM tools, and financial databases storing customer or supplier bank details benefit from IBAN validation at data entry time. Storing invalid IBANs creates problems when payments are eventually processed. Validation at entry time ensures data quality at the source.
4. Educational and Compliance Purposes
Finance professionals, developers building payment systems, and compliance officers learning about international banking standards use IBAN validators to understand the format requirements for different countries. Each country's BBAN format has specific rules that the validator can explain.
5. API Integration Testing
Developers building integrations with banking APIs, SWIFT networks, or payment processors need to test with valid IBAN numbers. Generating and validating test IBANs ensures that integration tests use properly formatted account numbers without requiring real banking credentials.
Tips & Best Practices
• IBANs are case-insensitive: IBANs are conventionally written in uppercase, but lowercase is technically valid. The validator handles both. When storing IBANs, standardize to uppercase for consistency.
• Remove spaces for processing: IBANs are often displayed with spaces every 4 characters for readability (e.g., DE89 3704 0044 0532 0130 00), but the spaces are not part of the IBAN. Strip spaces before validation or submission.
• Country codes determine expected length: Each country has a fixed IBAN length. If the IBAN validates as a valid format but the length doesn't match the country code, the account number is likely incorrect.
• Validation is not verification: A valid IBAN passes format and checksum checks, but that doesn't mean the account exists, is active, or belongs to the intended recipient. Only the bank can verify account existence.
• IBAN vs SWIFT/BIC: IBAN identifies the specific account; SWIFT/BIC (Business Identifier Code) identifies the bank. International transfers typically require both. The IBAN alone is sufficient for SEPA transfers within Europe.
• Remove spaces for processing: IBANs are often displayed with spaces every 4 characters for readability (e.g., DE89 3704 0044 0532 0130 00), but the spaces are not part of the IBAN. Strip spaces before validation or submission.
• Country codes determine expected length: Each country has a fixed IBAN length. If the IBAN validates as a valid format but the length doesn't match the country code, the account number is likely incorrect.
• Validation is not verification: A valid IBAN passes format and checksum checks, but that doesn't mean the account exists, is active, or belongs to the intended recipient. Only the bank can verify account existence.
• IBAN vs SWIFT/BIC: IBAN identifies the specific account; SWIFT/BIC (Business Identifier Code) identifies the bank. International transfers typically require both. The IBAN alone is sufficient for SEPA transfers within Europe.