IBAN Validator
Local only — nothing is uploaded unless you save or share it.
An IBAN checker that validates the country, the length and the check digits — and says which failed.
- Paste the IBAN — spaces, hyphens and lower case are all fine.
- Read the verdict: valid, or which of the three checks failed.
- If the checksum failed, compare the check digits it says the account needs.
Nothing is sent anywhere — the check runs in your browser.
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About this tool
Paste a bank account number and this IBAN checker tells you whether it can be a real one. An IBAN number check here is three checks rather than one: the country code has to be a country that issues IBANs, the length has to be the one that country registered, and then the mod-97 checksum has to hold. That matters because the checksum alone is not enough. A German IBAN with a digit missing is the wrong length, and about one in ninety-seven of those still passes a mod-97 check — so a tool that only runs the checksum will tell you a broken account number is fine. Running the length check first also means the answer can name what is wrong instead of just saying no. When the checksum does fail, it works out the check digits the rest of the account number would need and shows them. If you typed your own IBAN and transposed two digits, that is the fastest way to see it: the number says 12 and the account needs 50, so something in between is wrong. It also splits the national part into the bank code and the account number where the country's format is not in doubt, and shows it whole where it is — a wrong split would be a confident false statement about your bank details. The account number is not sent anywhere. Everything runs in your browser.
Frequently asked questions
How do I check IBAN numbers for free?
Paste one here. Three things are checked in order: that the first two letters are a country that issues IBANs, that the whole thing is the length that country registered — 18 characters for Denmark, 22 for Germany, 27 for France — and that the mod-97 checksum built into every IBAN works out. All three have to pass, and the page says which one did not.
What do the IBAN check digits actually prove?
That the characters have not been mistyped. The two digits after the country code are a check number: move the first four characters to the end, turn letters into numbers, and the whole thing divided by 97 must leave a remainder of 1. It catches a wrong digit and, usually, two digits swapped round. What it cannot do is tell you the account exists or belongs to who you think — only the bank knows that.
Why does it say the check digits should be something else?
Because the rest of the number tells us what they would have to be. The check digits are calculated from the country code and the account number, so when the checksum fails we can run that calculation and show the answer. If your IBAN says 12 and the calculation says 50, the mistake is almost certainly a digit somewhere in the middle rather than the check digits themselves.
Does a valid IBAN mean the money will arrive?
No, and this is the important limitation. You can validate IBAN digits all day: it only proves the number is correctly formed. It is not proof that the account is open, that it belongs to the person you are paying, or that the bank will accept the transfer — nothing here can verify bank account number ownership, because only the bank knows that. Plenty of fraud uses perfectly valid IBANs, so confirm the account with the person you are paying through a channel you already trust.
What is the bank code in my IBAN?
The first few characters after the check digits identify the bank, and how many depends on the country: Germany uses an eight-digit Bankleitzahl, Denmark a four-digit registration number, the UK four letters followed by a six-digit sort code. This splits the national part out where the country's format is not in doubt, and shows it whole where it is.
Is my account number uploaded?
No. The whole check is arithmetic that runs in your browser — there is no request to make, and it works with the network off once the page has loaded. That is worth knowing here more than on most pages, because what you are pasting is a bank account number.
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