IBAN Validator

It is exactly 29 characters: the two-letter country code UA, two check digits, six digits of the bank code and nineteen characters of the account itself. Spaces mean nothing — they are added in groups of four purely for readability and are not needed when entering the number in a bank.

It is the international check algorithm: the first four characters move to the end, letters are replaced by numbers, and the resulting long number is divided by 97. If the remainder is one, the number is written correctly. The method catches over 99% of typical mistakes: transposed digits, a missing or extra character. That is exactly why banks validate an IBAN before sending a payment.

Because mathematical correctness and a working account are different things. The number may be written flawlessly while the account is closed, blocked, belongs to someone else or is held in another currency. Another frequent cause is a mismatch between the recipient name on the payment and the actual account holder — banks reject those. Only the bank can confirm this.