How long is a Hungarian IBAN?

A Hungarian IBAN is always exactly 28 characters: the country code HU, two IBAN check digits, and a 24-digit BBAN. The BBAN holds a 3-digit bank code, 4-digit branch code, a national check digit, a 15-digit account number, and a second national check digit.

What are the two national check digits?

Hungary embeds two extra modulo-10 check digits inside the IBAN. One protects the 8-digit bank-plus-branch block and the other protects the 16-digit account block. Each is computed with the repeating weight pattern 9, 7, 3, 1 so that the weighted sum of each block is a multiple of 10.

How does the MOD-97-10 checksum work?

The first four characters (HU plus check digits) are moved to the end, letters are converted to numbers (H=17, U=30), and the whole string is reduced modulo 97. A structurally valid IBAN leaves a remainder of exactly 1.

Does a valid result mean the account is real?

No. A pass only means the IBAN is mathematically and structurally well-formed. It cannot tell you whether the account is open, funded, or owned by a particular person — only the holding bank can confirm that.

Why does my IBAN fail only the national check?

If the MOD-97 remainder is 1 but a national modulo-10 block fails, a digit inside the bank, branch, or account portion was mistyped in a way the IBAN checksum did not catch. The two national checks add an extra typo-detection layer specific to Hungary.

Hungary IBAN Validator

The Hungary IBAN Validator confirms that a Hungarian bank account number in IBAN format is structurally correct. It verifies the HU country code, the 28-character length, the bank and branch codes, the full ISO 7064 MOD-97-10 checksum, and the two Hungarian national modulo-10 check digits — all without sending a single character to a server.

Hungary uses one of the longest IBANs in the SEPA area. Domestic transfers settle through GIRO (batch) and VIBER (real-time gross settlement), and both rely on a correctly formed IBAN. A fast offline validator catches typos before they cause failed transfers in payroll runs, accounting imports, and checkout forms.

How it works

A Hungarian IBAN has a fixed structure from the SWIFT IBAN Registry:

HU — the country code for Hungary
kk — 2 IBAN check digits (ISO 7064 MOD-97-10)
bbb — 3-digit bank code
ssss — 4-digit branch code
x — 1 national check digit for the bank+branch block
15 digits — the account number
y — 1 national check digit for the account block

Total: 28 characters, with the entire BBAN made up of digits only.

Validation runs three independent checks:

IBAN MOD-97-10 — move HU plus the check digits to the end, expand letters to numbers, and confirm the result modulo 97 equals 1.
Bank/branch national check — over the 8-digit block (bank + branch + check digit), the weighted sum using the repeating pattern 9, 7, 3, 1 must be a multiple of 10.
Account national check — the same weighted modulo-10 rule applied across the 16-digit account block (account + its check digit).

Worked example

Take HU42 1177 3016 1111 1018 0000 0000:

Country code: HU
IBAN check digits: 42
Bank code: 117
Branch code: 7301
Bank/branch check digit: 6
Account: 111110180000000
Account check digit: 0

For the bank/branch block 11773016, multiply each digit by the weights 9 7 3 1 9 7 3 1 and sum; the total is divisible by 10, so the block passes. The account block is checked the same way, and the rearranged string reduces to a MOD-97 remainder of 1. All three checks pass, so the IBAN is valid.

Changing a single digit almost always breaks at least one of the three checksums, which is why Hungary’s triple-check IBAN is unusually robust against typos. Every character is processed locally — nothing is uploaded, logged, or transmitted.