IBAN Algorithm¶

SmartFaker implements the ISO 13616 standard for IBAN generation.

Structure¶

An IBAN is composed of:

Country code — 2 uppercase letters
Check digits — 2 numeric digits
BBAN — country-specific Basic Bank Account Number

Generation flow¶

The country-specific BBAN generator produces a BBAN of the documented length (COUNTRY_GENERATORS[code]["length"] minus four).
calculate_check_digits() computes the MOD-97 check digits.
The candidate IBAN is assembled and re-validated with validate_iban() before being returned.

MOD-97 check¶

For check-digit calculation, the temporary string is constructed as BBAN + country + "00". Each letter is replaced with its numeric equivalent (A=10, B=11, …, Z=35), the result is interpreted as one big integer, and the check digits are 98 - (n mod 97) (zero-padded).

Validation reverses the construction: BBAN + country + check mod 97 must equal 1.

Country-specific quirks¶

Italy / San Marino — the BBAN starts with a CIN check character computed from a 26-element weight table.
Belgium — the BBAN ends with two check digits derived from the bank code + account number using mod-97.
France / Monaco — include a 2-digit numeric key after the account.
Germany / UK / US — the bank code is selected from a curated list of well-known real bank codes for realism.

The full per-country layout is encoded in country_data inside smartfaker.iban — read the source for the exact field order.