IBAN Validator (ISO 13616)
Validate structural, country-specific, and mathematical integrity of any global IBAN according to ISO 7064 Modulo 97-10 and SWIFT registry rules.
How IBAN Validation Works
The validator checks the issuing jurisdiction code against ISO 3166-1, validates the exact length and regex pattern of the national BBAN against the SWIFT official registry.
It then performs the Modulo 97-10 algorithm by shifting the first 4 characters to the end, substituting letters with numbers, and calculating BigInt remainder 97. If the remainder equals 1, the account number is verified.
IBAN Verification Checkpoints
A successful validation satisfies all regulatory compliance stages:
| Stage | Rule | Requirement | Validator Operation | Expected Result |
|---|---|---|---|---|
| 1 | Country Code Match | 2 letters | Verifies that the prefix matches an active SWIFT registered country. | GB (United Kingdom) |
| 2 | Length Check | Strict | Compares overall length against national law specifications. | 22 characters for GB |
| 3 | BBAN Regex Pattern | Alphanumeric | Ensures numeric and alphabetical positions match country formatting. | 4 letters + 14 digits |
| 4 | ISO 7064 MOD 97 Checksum | MOD 97-10 | Validates cyclic modular arithmetic on the full character sequence. | Remainder == 1 |
Modulo 97 Mathematical Verification
The algorithm verifies that the sequence is mathematically congruent:
- 1. Remove all spaces and display formatters.
- 2. Move the first 4 characters to the very end of the string.
- 3. Replace letters A through Z with numbers 10 through 35.
- 4. Calculate division remainder modulo 97: if remainder is exactly 1, the IBAN is valid.