Validators
Check IBANs and national ID or tax numbers (Spain, Brazil, Poland) against their official check-digit rules, in your browser.
4 tools in this category. Every tool runs in the browser and needs no sign-up.
IBAN Validator — Check IBAN Numbers Online (Batch)
Check IBANs for the correct length, country format and mod-97 check digits. Paste up to 500 IBANs, one per line; see the country, the formatted IBAN and what is wrong. Runs in your browser.
DNI / NIE Letter Calculator — Validate Spanish NIF and NIE
Calculate the control letter of a Spanish DNI or NIE and validate full numbers: 12345678 → 12345678Z, X1234567 → X1234567L. Paste up to 500 numbers, one per line.
CPF / CNPJ Validator and Generator — Including Alphanumeric CNPJ
Validate Brazilian CPF and CNPJ numbers, including the new alphanumeric CNPJ from July 2026, and generate valid test numbers for software testing. Batch, formatted output, runs in your browser.
PESEL / NIP / REGON Validator — Check Polish ID and Tax Numbers
Validate Polish PESEL, NIP and REGON numbers by their check digits, and read the date of birth and sex from a PESEL. Paste up to 500 numbers, one per line.