Polish NIP Tax ID Validator
Validate structural compliance and check digits of Polish NIP tax numbers.
About Polish NIP Validation
Validation checks 10-digit length, removes optional `PL` prefix, and calculates the weighted Modulo 11 check digit.
Essential for verifying corporate and tax registrations in Poland.
Anatomy & Structure of Polish NIP
The NIP consists of 10 decimal digits regulated by the Ministry of Finance:
| Position | Field | Length | Meaning & Rule | Example |
|---|---|---|---|---|
| 1 to 3 | Tax Office Code | 3 digits | Code of the issuing tax office (Urząd Skarbowy) | 123 |
| 4 to 9 | Sequential Number | 6 digits | Unique taxpayer sequential counter | 456321 |
| 10 | Check Digit | 1 digit | Security digit computed via weighted Modulo 11 | 8 |
NIP Calculation & Validation Algorithm (Modulo 11)
NIP validation uses positional weights and Modulo 11 division:
DV = (∑ di × Weights[i]) mod 11 (Weights: 6, 5, 7, 2, 3, 4, 5, 6, 7)
- 1. Remove spaces, hyphens, and 'PL' prefix if present.
- 2. Validate that the sequence has exactly 10 numeric digits.
- 3. Multiply the first 9 digits by the weights [6, 5, 7, 2, 3, 4, 5, 6, 7].
- 4. Calculate the remainder of the weighted sum divided by 11.
- 5. Reject numbers where remainder equals 10 (invalid by tax regulations).
- 6. Compare the obtained remainder against the 10th digit.