What this checker verifies
Every identifier below carries either check digits or a fixed structure. Typos — a wrong digit, two swapped characters, a character too many — are caught by the check-digit arithmetic alone, without asking any database. That is all this page does: it runs the published algorithms in your browser. It cannot tell you whether an account exists, whether a BIC is live in the SWIFT network or whether an LEI has lapsed; those need a look-up in the bank's, SWIFT's or GLEIF's systems.
| Identifier | Standard | What is checked |
|---|---|---|
| IBAN | ISO 13616 | Country code, length for that country (SWIFT IBAN registry, 89 countries plus national IBANs not yet in the registry), MOD 97-10 check digits |
| BIC / SWIFT code | ISO 9362 | 8 or 11 characters, ISO 3166 country code; notes test BICs (location ending in 0), passive participants (ending in 1) and the XXX primary-office branch. BICs have no check digit. |
| LEI | ISO 17442 | 20 characters, MOD 97-10 check digits in positions 19–20 |
| ABA routing number | ABA / Federal Reserve | 9 digits, 3-7-1 weighted check digit, valid prefix (00–12, 21–32, 61–72, 80) and Federal Reserve district |
| SEPA creditor identifier | EPC SDD rulebooks | MOD 97-10 check digits over the national identifier and country code; the business code is excluded |
| RF creditor reference | ISO 11649 | “RF”, two check digits, up to 21 characters, MOD 97-10 |
| ISIN | ISO 6166 | 12 characters, Luhn check digit over the letters converted to numbers; shows the embedded CUSIP (US, CA) or SEDOL (GB) |
| CUSIP | ANSI X9.6 | 9 characters, modulus-10 “double-add-double” check digit; shows the matching US ISIN |
| SEDOL | London Stock Exchange | 7 characters without vowels, weights 1-3-1-7-3-9; shows the matching GB ISIN |
How the check digits work
MOD 97-10 (IBAN, LEI, creditor identifier, RF reference). Letters become numbers (A = 10 … Z = 35), the country code and check digits are moved to the end where the standard requires it, and the whole number divided by 97 must leave a remainder of 1. Any single wrong character and almost every swap of two characters changes the remainder.
ABA routing numbers multiply the nine digits by 3, 7, 1, 3, 7, 1, 3, 7, 1; the sum must be a multiple of 10. ISIN uses the Luhn algorithm on the digit string, CUSIP doubles every second character before adding the digits of each product, and SEDOL uses the weights 1, 3, 1, 7, 3, 9 for its first six characters.
A valid result therefore means “no typo”, not “the account or company exists”. The checker deliberately does not compute corrected check digits for an invalid IBAN: a corrected-looking number for the wrong account is worse than an error.
Checking whole files
Paste up to 5,000 lines at once and export the result as CSV. To check the identifiers inside payment and reporting files in context, use the Bite Apps tools — they run the same algorithms on every field: SafeCAMT for IBANs, BICs, creditor identifiers and RF references in pain.001, pain.008, camt.053 and MT940 files; SafeACH for routing numbers in NACHA files; SafeDORA for LEIs in the DORA register of information.
FAQ
Is anything I paste sent to a server?
No. The checks run in JavaScript in this browser tab. The page's Content-Security-Policy blocks every network destination, and the badge above counts requests since the page loaded — you can confirm it in your browser's DevTools Network tab.
Does a valid IBAN mean the account exists?
No. The check digits prove that the IBAN is well-formed and has no typo. Whether the account exists and who holds it can only be confirmed by the bank, for example through the SEPA Verification of Payee check when you send a credit transfer in euro.
Why does my BIC show as valid although my bank says it is wrong?
BICs have no check digit. This page checks the format and the country code, but not whether the BIC is registered or active; that requires the SWIFT BIC directory.
Can it check an LEI against GLEIF?
It verifies the ISO 17442 check digits, which catches typos. Whether an LEI is issued, current or lapsed requires a look-up in the GLEIF database, which this offline page deliberately does not make.
What is the difference between an ABA routing number and a CUSIP?
Both can be nine digits. The checker tries both algorithms and shows every interpretation whose check digit matches, so a nine-digit number may appear as “ABA routing number or CUSIP”.
Which countries use IBAN?
The SWIFT IBAN registry lists 89 countries, from Albania (28 characters) to Yemen (30). Norway has the shortest IBAN with 15 characters, Russia the longest with 33. Several African countries use IBAN-format account numbers nationally that are not yet in the registry; the checker accepts them and says so.