IBAN, NIP, REGON & PESEL validator
Check bank account numbers and Polish tax, business and personal ID numbers. The check digits are verified in your browser.
| Number | Type | Result | Details |
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The check is purely mathematical: it confirms that a number is well formed, not that the account, company or person exists.
How to check an IBAN or a Polish ID number
- Paste one or more numbers, each on its own line; spaces and dashes are ignored.
- Leave automatic detection on or choose the type: IBAN, NIP, REGON or PESEL.
- Press Check to verify the check digits of every number at once.
- Read the result table: valid numbers show useful details such as the country or the date of birth.
- Copy the results to your spreadsheet if you are cleaning a customer or supplier list.
When it helps
- Catching a typo in a bank account number before sending a transfer.
- Verifying the NIP of a new client before issuing the first invoice.
- Cleaning a list of contractors imported from another system.
- Checking a REGON from a contract or a public tender document.
- Reading the date of birth and sex encoded in a PESEL number.
Frequently asked questions
How is an IBAN validated?
The tool checks the country code, the length required for that country and the two check digits calculated with the modulo 97 method from the ISO 13616 standard.
What do NIP, REGON and PESEL mean?
They are Polish identifiers: NIP is the tax number, REGON the statistical business number and PESEL the national personal identification number.
Does a valid result mean the company exists?
No. A correct check digit only proves the number is well formed. To confirm that a business is active, use the official public registers.
Can I check many numbers at once?
Yes. Paste a whole column from a spreadsheet; each line is checked separately and the summary shows how many numbers passed.
Which details does a PESEL reveal?
The first six digits encode the date of birth, including the century, and the tenth digit shows the sex. The tool decodes both.
Are the numbers sent to a server?
No. All checks run in your browser, which matters for personal data such as PESEL numbers.