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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.

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The type is detected from the length: 11 digits PESEL, 10 NIP, 9 or 14 REGON. Only check digits are verified, not the registers.

Up to 100,000 UTF-16 units per input and 1,000,000 per result. See the supported formats and examples below.

Result

Add your input or load an example, then run the tool. Your result will appear here.

How to use

  1. Paste PESEL, NIP or REGON numbers, one per line (NIP may include PL and dashes).
  2. Run the check.
  3. Each line shows ✓ or ✗ and the type; a valid PESEL also shows the date of birth and sex.

Example

44051401359 → ✓ PESEL, 1944-05-14, male
123-456-32-18 → ✓ NIP

Details and limitations

PESEL encodes the birth date: the month has 20 added for 2000–2099 (and 80, 40, 60 for other centuries), and the tenth digit is odd for men and even for women.

Check digits: PESEL weights 1-3-7-9, NIP weights 6-5-7-2-3-4-5-6-7 (mod 11), REGON 8-9-2-3-4-5-6-7 (mod 11). Numbers stay in your browser.

FAQ

How do I read the date of birth from a PESEL?

The first six digits are YYMMDD. For people born in 2000 or later, 20 is added to the month: 02 in position 3–4 means February 19xx, 22 means February 20xx.

Can it tell whether a NIP is active for VAT?

No. Use the official VAT taxpayer list (biała lista) for that; this tool only checks the number’s check digit.

Is a number with a correct check digit always real?

No. It is only internally consistent; it may not be assigned to anyone.

Format references

Tool page updated: