IBAN Code Calculator (Validate & Generate)
Use this tool to verify an International Bank Account Number (IBAN) or calculate valid check digits for a new IBAN from a country code and BBAN.
1) Validate an IBAN
2) Generate IBAN Check Digits
What Is an IBAN Code Calculator?
An IBAN code calculator helps you work with International Bank Account Numbers in two important ways: validation and generation. Validation checks whether an IBAN follows the official format and checksum rules. Generation calculates the two check digits that appear after the country code, helping you build a complete IBAN from a known BBAN.
IBANs are used globally to reduce payment errors, especially in cross-border transfers. A single character mistake can cause delays, rejection fees, and reconciliation issues. That is why a fast, reliable calculator can be valuable for finance teams, developers, freelancers, and anyone sending international payments.
Why IBAN Validation Matters
When an IBAN fails validation, it does not always mean the account does not exist. It usually means the number does not satisfy one or more structural rules. Most often, errors happen because of:
- Missing or extra characters
- Incorrect country code or wrong IBAN length for that country
- Typos in the check digits
- Copy/paste mistakes with spaces and special characters
Running a quick check before submitting a bank transfer can save time and avoid costly returns.
How the IBAN Checksum Works (MOD 97)
Step-by-step process
The IBAN checksum is based on the ISO 13616 standard and uses a MOD 97 algorithm:
- Take the IBAN and move the first 4 characters to the end.
- Convert letters to numbers (A=10, B=11, ... Z=35).
- Treat the result as a very large number.
- Compute that number modulo 97.
- A valid IBAN must produce a remainder of 1.
For generating check digits, the same process is used with placeholder digits 00, and then the calculator computes: 98 - remainder.
How to Use This IBAN Code Calculator
To validate an IBAN
- Paste or type your IBAN in the validator field.
- Click Validate IBAN.
- Read the result message for validity, formatting, and possible errors.
To generate an IBAN
- Enter a 2-letter country code (for example, FR, DE, ES, NL).
- Enter the BBAN exactly as provided by the bank.
- Click Generate IBAN.
- The tool calculates and returns a full IBAN with proper check digits.
IBAN vs SWIFT/BIC: Quick Clarification
People often confuse IBAN and SWIFT/BIC, but they serve different functions:
- IBAN: identifies a specific account in a specific country.
- SWIFT/BIC: identifies the receiving bank institution.
Many international payments require both.
Common Mistakes to Avoid
- Assuming all countries use the same IBAN length (they do not).
- Removing leading zeros from BBAN parts.
- Entering lowercase or extra symbols from copied text.
- Relying only on format checks without confirming beneficiary details.
Important Note on Accuracy and Compliance
This calculator validates IBAN structure and checksum logic. It does not confirm that an account is open, active, or belongs to a specific person or company. Always verify beneficiary identity and comply with your bank's KYC/AML and payment verification procedures.
Frequently Asked Questions
Can a valid IBAN still fail a transfer?
Yes. A valid IBAN can still be rejected due to account status, compliance checks, incorrect recipient name, or payment route restrictions.
Does spacing matter in IBAN input?
No. Spaces are ignored by the calculator. The algorithm evaluates only alphanumeric characters.
Is this suitable for developers?
Yes. This page uses a clear JavaScript implementation of IBAN normalization, alphanumeric conversion, and MOD 97 checksum logic, making it easy to inspect or adapt for internal tools.