IBAN Number Validator

Validate International Bank Account Numbers with instant verification, checksum calculation, and format validation for all SEPA countries

Secure Validation
35+ Countries
Instant Results
Banking Standard

IBAN Number Validator

What is an IBAN (International Bank Account Number)?

An 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 identify bank accounts across national borders. The IBAN system is primarily used in Europe and other regions for international money transfers.

IBAN Structure

DE89 3704 0044 0532 0130 00

DE: Country Code (Germany)
89: Check Digits
3704 0044 0532 0130 00: Basic Bank Account Number (BBAN)

Key Features

  • Standardized format across participating countries
  • Built-in error detection through checksum validation
  • Facilitates automated payment processing
  • Reduces payment errors and processing time

Technical Implementation and Validation

Mod-97 Algorithm

IBAN validation uses the ISO 13616 mod-97 algorithm for checksum verification:

Step 1: Move first 4 characters to end
Step 2: Replace letters with numbers (A=10, B=11...)
Step 3: Calculate mod 97 of the result
Step 4: Valid if remainder equals 1

Example Calculation

Original IBAN: GB82 WEST 1234 5698 7654 32
Rearranged: WEST12345698765432GB82
Numeric: 3214281912345698765432161182
3214281912345698765432161182 mod 97 = 1 ✓

Country-Specific Rules

Each country has specific IBAN formatting requirements:

Germany (DE)
22 characters: DEkk bbbb bbbb cccc cccc cc
United Kingdom (GB)
22 characters: GBkk bbbb ssss sscc cccc cc
France (FR)
27 characters: FRkk bbbb bsss sscc cccc cccc cxx

Applications and Use Cases

Banking & Finance

  • • International wire transfers
  • • SEPA credit transfers
  • • Direct debit mandates
  • • Account verification
  • • Payment processing
  • • Compliance validation

Business Operations

  • • Payroll management
  • • Vendor payments
  • • Customer refunds
  • • Subscription billing
  • • International trade
  • • Financial reporting

Software Development

  • • Payment gateway integration
  • • Banking API validation
  • • Form input validation
  • • Data quality assurance
  • • Financial software testing
  • • Compliance automation

Real-World Scenarios

E-commerce Platform

An international e-commerce platform validates customer IBAN numbers during checkout to ensure refunds can be processed correctly, reducing failed transactions and customer service inquiries.

Payroll System

A multinational company uses IBAN validation to verify employee bank accounts before processing salary payments, ensuring compliance with local banking regulations across different countries.

How to Use the IBAN Validator: Step-by-Step Tutorial

Single IBAN Validation

1

Enter IBAN Number

Type or paste the IBAN you want to validate. Spaces are automatically handled.

2

Click Validate

The system performs mod-97 checksum validation and format verification.

3

Review Results

See validation status, country information, and formatted IBAN.

Bulk Validation

1

Prepare IBAN List

Create a list of IBANs, one per line in the bulk validation textarea.

2

Validate All

Click "Validate All IBANs" to process the entire list simultaneously.

3

Analyze Results

Review the validation summary and individual results for each IBAN.

Best Practices

⚠️

Always Validate Before Processing

Validate IBANs before initiating any financial transactions to prevent errors.

💡

Use Country Selection

Select the appropriate country to generate sample IBANs for testing.

🔒

Data Security

All validation is performed client-side for maximum security and privacy.

Common Validation Errors

Invalid Length: IBAN doesn't match country-specific length requirements
Checksum Failed: Mod-97 algorithm validation returned incorrect result
Invalid Characters: Contains non-alphanumeric characters
Unsupported Country: Country code not recognized or supported

Practical Examples and Use Cases

Valid IBAN Examples

GB82 WEST 1234 5698 7654 32
United Kingdom - Westpac Bank
DE89 3704 0044 0532 0130 00
Germany - Commerzbank
FR14 2004 1010 0505 0001 3M02 606
France - BNP Paribas

Invalid IBAN Examples

GB83 WEST 1234 5698 7654 32
Invalid check digits (83 instead of 82)
DE89 3704 0044 0532 013
Incorrect length (19 instead of 22)
XY12 3456 7890 1234 5678 90
Invalid country code (XY)

Integration Examples

JavaScript Validation

function validateIBAN(iban) {
const cleanIban = iban.replace(/\s/g, '').toUpperCase();
// Move first 4 chars to end
const rearranged = cleanIban.slice(4) + cleanIban.slice(0, 4);
// Convert to numeric
const numeric = rearranged.replace(/[A-Z]/g,
char => (char.charCodeAt(0) - 55).toString());
// Check mod 97
return BigInt(numeric) % 97n === 1n;
}

Python Implementation

def validate_iban(iban):
clean_iban = iban.replace(' ', '').upper()
rearranged = clean_iban[4:] + clean_iban[:4]
numeric = ''
for char in rearranged:
if char.isdigit():
numeric += char
else:
numeric += str(ord(char) - 55)
return int(numeric) % 97 == 1

Frequently Asked Questions

What is the difference between IBAN and SWIFT codes?

IBAN identifies specific bank accounts, while SWIFT codes identify banks or financial institutions. IBAN is used for account identification in transfers, whereas SWIFT codes route the transfer to the correct bank. Both are often required for international wire transfers.

Can I validate IBANs for all countries?

Our validator supports all countries that have adopted the IBAN standard, including all EU member states, plus Norway, Switzerland, Iceland, Liechtenstein, and many other countries. We support over 35 countries with their specific formatting rules and length requirements.

Is my data secure when using this validator?

Yes, all IBAN validation is performed entirely in your browser using client-side JavaScript. No IBAN data is transmitted to our servers or stored anywhere. The validation happens locally on your device, ensuring maximum privacy and security for sensitive financial information.

Why do some valid-looking IBANs fail validation?

IBAN validation involves multiple checks: country code recognition, length verification, character validation, and most importantly, the mod-97 checksum algorithm. Even if an IBAN looks correct, it must pass the mathematical checksum test. The check digits are calculated using a specific algorithm, and any error in the account number will cause validation to fail.

Can I use this tool for commercial purposes?

Yes, this IBAN validator is free to use for both personal and commercial purposes. However, for high-volume commercial applications, we recommend implementing server-side validation and considering additional verification steps, such as bank account verification services for critical financial operations.

What should I do if an IBAN validation fails?

If validation fails, first check for common errors: typos in the account number, incorrect country code, missing or extra characters, or wrong check digits. Double-check the IBAN with the account holder or their bank. Some older account numbers may need to be converted to IBAN format by the issuing bank.

How accurate is the mod-97 algorithm?

The mod-97 algorithm used in IBAN validation is highly accurate and can detect most common errors including single digit errors, transposition of adjacent digits, and many other types of data entry mistakes. However, it's not 100% foolproof - there's approximately a 1 in 97 chance that an incorrect IBAN could still pass validation due to coincidental checksum matching.

Can I validate IBANs in bulk for large datasets?

Yes, our tool supports bulk validation where you can paste multiple IBANs (one per line) and validate them all at once. For very large datasets (thousands of IBANs), consider breaking them into smaller batches for optimal performance. The bulk validation feature provides a summary of valid vs invalid IBANs.

Built with precision and security in mind. All validation performed client-side for maximum privacy.
Supporting international banking standards and SEPA compliance requirements.