Master IBAN Calculation
Everything you need to know about International Bank Account Numbers: calculation, validation, troubleshooting, and country-specific formats for 60+ countries.
Understanding IBANs
Learn the fundamentals of International Bank Account Numbers and why they're essential for global banking.
The International Bank Account Number (IBAN) is a standardized system for identifying bank accounts across 88 countries. Established by the ISO 13616 standard, it reduces errors in cross-border transactions.
Key Benefits:
- • Reduces transcription errors by up to 97%
- • Standardizes international payments
- • Contains built-in validation via check digits
- • Enables automated payment processing
An IBAN consists of up to 34 alphanumeric characters with four key components:
The MOD-97 Algorithm
Understanding how IBAN check digits are calculated using the ISO 7064 MOD-97-10 algorithm.
This matches the expected result, confirming our algorithm works correctly for Algeria.
- • Single character substitution (4234 → 1234)
- • Adjacent character transposition (12354 → 12345)
- • String shifting (left or right)
- • Character omission or duplication
- • Double substitution errors (97%+ detection)
- • Non-adjacent transposition (95%+ detection)
- • Multiple random errors (varies by pattern)
Country-Specific Formats
IBAN structures vary by country. Here are the most commonly requested formats and troubleshooting scenarios.
Full Support (Generation + Validation)
Validation Only (83 Additional Countries)
Troubleshooting & FAQs
Common issues and solutions based on real user problems and edge cases.
Root Cause Analysis:
- BBAN Structure Misunderstanding: Algeria uses National(2) + Bank(3) + Branch(5) + Account(10) = 20 digits
- Missing National Check: Input has 18 digits, missing the 2-digit national RIB key
- Incorrect Parsing: System treated the input as bank+branch+account without national prefix
Solution:
We've fixed the BBAN construction to properly handle Algeria's format:
IBAN shows as invalid
- • Check the country code (2 letters)
- • Verify total length matches country standard
- • Ensure no spaces or special characters
- • Confirm check digits are numeric (02-98)
Length mismatch errors
- • Algeria: exactly 24 characters
- • France: exactly 27 characters
- • Germany: exactly 22 characters
- • Each country has fixed IBAN length
Missing bank/branch codes
- • Germany requires 8-digit BLZ code
- • UK needs 4-digit bank + 6-digit sort code
- • France needs 5-digit bank + branch codes
- • Contact your bank for correct codes
Country not supported for generation
- • Use validation-only mode
- • Get complete IBAN from your bank
- • Request support via contact form
- • Check for updates regularly
🔒 Is my banking data secure?
Absolutely! All IBAN calculations happen locally in your browser. We never send account numbers, IBANs, or sensitive data to our servers. Only anonymous usage statistics (country, success/failure) are collected to improve the service.
🌍 Which countries are supported?
We support validation for all 88 IBAN countries according to theISO 13616 standard. IBAN generation (from account numbers) is available for popular countries like Algeria, France, Germany, UK, and Spain.
🔢 Can I calculate IBAN from just my account number?
It depends on the country. Algeria allows calculation from account numbers (if they include bank/branch codes). Other countries like Germany require additional information like BLZ codes, and UK needs sort codes.
🏦 What if my country isn't supported for generation?
You can still use our validator with complete IBANs. For generation support, contact your bank for the complete IBAN, or submit a request via our contact form. We regularly add new countries based on user demand.
❌ Why does validation fail for a bank-issued IBAN?
Bank-issued IBANs should always be valid. If validation fails, check for typos, ensure correct country format, or contact your bank. Some banks may use internal formats that differ from standard IBAN specifications.
🔄 How often is the country data updated?
We regularly sync with theSWIFT IBAN Registryand monitor ISO 13616 updates. New countries and format changes are added within weeks of official announcements.