IBAN Check Digit Calculator
Compute the two ISO 7064 mod-97-10 check digits for an IBAN and validate an existing one — for cross-border bank transfers.
About IBAN Check Digit Calculator
IBAN Check Digit Calculator computes the two ISO 7064 mod-97-10 check digits for an International Bank Account Number and validates existing ones — so cross-border transfers don't bounce on a mistyped digit.
How to use IBAN Check Digit Calculator
- 1Paste or type your input into the box above — a sample is pre-filled so you can try it instantly.
- 2Set any options on offer (mode, key, format) to match what you need.
- 3The result appears the moment you type — no button to press, no waiting.
- 4Click Copy to grab the output — IBAN Check Digit Calculator keeps everything on your device.
Why use IBAN Check Digit Calculator?
- ✓Filling in the check digits when constructing an IBAN from a BBAN
- ✓Validating a customer-supplied IBAN before submitting a SEPA transfer
- ✓Understanding why an IBAN was rejected as invalid
- ✓100% free with no sign-up, no watermark and no usage limits
- ✓Runs entirely in your browser — your text and keys are never uploaded, stored or logged
- ✓Works offline once loaded, with instant results and one-click copy
Frequently asked questions
How are IBAN check digits calculated?+
Move the 4-character country code and check digits to the end, replace each letter with two digits (A=10 … Z=35), interpret the result as one big integer, and the check digits are 98 minus that number modulo 97. A correct IBAN gives a remainder of exactly 1 when validated.
Does a valid IBAN mean the account exists?+
No — the mod-97 check only confirms the IBAN is well-formed and free of typos. It does not verify that the bank or account actually exists; that requires a bank-side lookup.
Is it free to use?+
Yes — completely free with no sign-up, no account and no usage limits. There is no paywall, so you can encode, decode and convert as much as you like.
Is my data private and secure?+
Yes. This tool runs entirely in your browser using client-side JavaScript — your input is never uploaded to a server, stored or logged. Once the page has loaded you can use it offline, which makes it safe for tokens, keys and confidential data.
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