IBAN Calculator: Generate and Validate
Use this tool to calcular IBAN check digits, build a complete IBAN from country + BBAN, or validate an existing IBAN before making a transfer.
What does “iban calcular” mean?
If you searched for iban calcular, you are usually trying to do one of two things: compute valid IBAN check digits for a bank account, or verify whether a full IBAN is mathematically correct. Both are important before sending international payments with SEPA or SWIFT.
An IBAN (International Bank Account Number) is a standardized format used in many countries to reduce payment errors. It includes a country code, two control digits, and a BBAN (Basic Bank Account Number).
How an IBAN is structured
- Country code: 2 letters (for example, ES, DE, FR, IT).
- Check digits: 2 numbers calculated using the MOD-97 algorithm.
- BBAN: The domestic account format used by that specific country.
Example: ES91 2100 0418 4502 0005 1332 where ES is the country and 91 are the check digits.
How IBAN check digits are calculated
Step-by-step formula
- Take the BBAN and prepend country code +
00. - Move the first 4 characters to the end.
- Convert letters to numbers (A=10, B=11, ..., Z=35).
- Compute the remainder of the long number mod 97.
- Check digits =
98 - remainder(always two digits).
This is the same standard used by banks and payment systems. A valid IBAN must satisfy the rule that the final converted number modulo 97 equals 1.
Generate vs Validate: when to use each mode
Generate mode
Use this when you know the country and BBAN and need the correct 2-digit IBAN checksum. This is common in integrations, ERP imports, billing tools, and data migrations.
Validate mode
Use this when you receive a full IBAN and want to verify if it is formally valid before processing payment instructions.
Common mistakes when trying to calcular IBAN
- Including spaces or punctuation from copied IBAN text.
- Using the wrong country code for a domestic account.
- Confusing BBAN length (which differs by country).
- Assuming a mathematically valid IBAN always corresponds to an open bank account (it does not).
Important security and compliance notes
IBAN validation only confirms mathematical structure. It does not confirm account ownership, AML/KYC status, or whether an account is active. For production payment systems, combine IBAN checks with bank verification services, fraud controls, and beneficiary confirmation workflows.
Quick FAQ
Can I calculate an IBAN for Spain (IBAN España)?
Yes. Enter ES and the BBAN in Generate mode. The tool computes the two IBAN check digits.
Does this tool support SEPA countries only?
It supports many IBAN countries. Length checks are applied for recognized country codes to improve accuracy.
Why does a valid IBAN still fail a transfer?
Because validity is only one layer. Transfers can fail due to blocked accounts, incorrect beneficiary data, sanctions rules, or bank-side restrictions.