What Is a NIP Number?

NIP stands for Numer Identyfikacji Podatkowej, Poland's tax identification number. The head of the local tax office issues each NIP as a unique 10-digit code assigned to every business entity and certain other taxpayers ^[1][2]. Since 2012, individuals without a registered business use PESEL as their tax identifier instead ^[2].

NIP functions as both a domestic tax ID and a VAT number, so you'll see it called a "VAT NIP number" or "Polish tax identification number" in English-language documents. For EU cross-border transactions, the same 10 digits get a "PL" prefix (e.g., PL1234567890) to form the EU VAT identification number.

How the Checker Works

The tool runs two checks on any 10-digit NIP you enter:

Checksum verification. It multiplies each of the first nine digits by the weights 6, 5, 7, 2, 3, 4, 5, 6, 7, sums the products, and divides by 11. If the remainder matches the tenth digit, the checksum is valid. A remainder of 10 means the number cannot exist.

Tax office prefix decode. The first three digits identify which urząd skarbowy (tax office) originally assigned the NIP. The tool maps this code to the office name.

A valid checksum confirms the number follows the correct mathematical pattern. It does not confirm the NIP is currently active or registered. For active status, use the official NIP status checker at podatki.gov.pl ^[3] or the VAT taxpayer registry (biała lista) ^[4].

Why Verify a Contractor's NIP Before Invoicing?

Polish tax law requires a valid NIP on every VAT invoice. An incorrect NIP can trigger invoice rejection or complications during a tax audit. A failed checksum means the number is wrong: a typo, transposed digits, or a fabricated sequence. Catch it before the invoice goes out.

For transactions above 15,000 PLN, you're also required to verify the contractor's bank account against the biała lista ^[5]. Paying to an account not on the white list can cost you the tax deduction and trigger joint VAT liability ^[5]. This tool handles step one (structural validity). The biała lista at podatki.gov.pl handles step two (VAT registration and bank account matching) ^[4].

NIP vs. VIES

This checker validates the Polish domestic format: 10 digits, no prefix. For EU VAT numbers with a country prefix, use the European Commission's VIES system ^[6], which queries national tax databases across all 27 member states in real time.

If you receive a VAT number starting with "PL," strip the prefix and enter the 10 digits here. If it starts with "DE," "CZ," or any other country code, go to VIES.

NIP Format and Structure

A NIP contains exactly 10 digits. No letters, no spaces, no hyphens in the current format.

Digits 1–3: Tax office code. The tool decodes this prefix and displays the corresponding office name.

Digits 4–9: Serial number assigned to the taxpayer. These digits carry no encoded meaning ^[1].

Digit 10: Check digit. The mod-11 algorithm with weights 6, 5, 7, 2, 3, 4, 5, 6, 7 produces this digit from the first nine. If the calculation yields a remainder of 10, no valid NIP can use that combination.

Older documents sometimes show NIP with hyphens (123-456-78-90 or 123-45-67-890). Both formats represent the same number. Enter it without hyphens.

Who Needs a NIP?

Companies registered in Poland (sole traders through CEIDG, commercial companies through KRS), foreign companies with a Polish tax obligation, VAT-registered entities, and employers or tax remitters (płatnicy) all receive a NIP ^[2].

If you're a foreigner working in Poland as an employee, you don't need one. Your PESEL covers tax identification. If you register a business, you receive a NIP automatically through the CEIDG registration process, and the tax office issues it within 3 days ^[2].

Need Full Company Information?

This checker verifies mathematical validity and decodes the tax office prefix. It doesn't return company names, addresses, or registration status. For full company data, use these official registries (all accept NIP as a search parameter):

• CEIDG (Centralna Ewidencja i Informacja o Działalności Gospodarczej) for sole traders and civil partnerships ^[7]
• KRS (Krajowy Rejestr Sądowy) for commercial companies such as sp. z o.o. and S.A. ^[8]
• Biała lista for VAT registration status and registered bank accounts ^[4]

Common Questions

Does the tax office prefix tell me where a company is located now?

No. The first three digits reflect where the NIP was originally issued, not where the taxpayer currently operates. Companies can relocate without their NIP changing.

Can I use a Polish NIP for intra-EU transactions?

Yes, but you need to add the "PL" prefix. Your EU VAT number is "PL" followed by your 10-digit NIP. Your trading partner's country may want to verify it through VIES ^[6], which is the EU-wide validation system.

References

1. Act on Taxpayer Registration and Identification — Consolidated Text (2025) — isap.sejm.gov.pl
2. What Is NIP — Official Government Guide — biznes.gov.pl
3. NIP Status Checker — podatki.gov.pl
4. VAT Taxpayer Registry (White List) — podatki.gov.pl
5. White List of VAT Taxpayers Guide — biznes.gov.pl
6. VIES VAT Number Validation — ec.europa.eu
7. CEIDG Business Registry Search — aplikacja.ceidg.gov.pl
8. Portal of Court Registries — KRS Search — prs.ms.gov.pl