What this NIP validator does
This tool normalizes a Polish NIP number, removes an optional PL prefix, checks the length and digits, validates the checksum and shows a simple technical breakdown.
Validation result
Enter a 10-digit NIP number to check the format and checksum.
This tool checks only NIP format and checksum. It does not confirm that a business exists.
It does not check VAT status and does not query KAS, CEIDG, GUS or any official register.
A technically valid NIP can still be inactive, revoked, unregistered or unrelated to the company you are checking.
How to use it
Paste the NIP with or without spaces, hyphens or PL prefix, then run the validation. Review the normalized number and checksum result before using the output elsewhere.
NIP format
A Polish NIP contains ten digits. The first digits are often associated with the tax office prefix, the middle digits form the body of the number and the final digit is the checksum.
NIP checksum algorithm
The validator multiplies the first nine digits by the weights 6, 5, 7, 2, 3, 4, 5, 6, 7, sums the result and calculates the checksum as sum mod 11. If the calculated value is 10, the NIP is technically invalid.
Practical guidance
What this tool cannot verify
A technically valid NIP can still belong to a different entity than you expect, may be inactive or may not be usable for a real transaction. This page does not query KAS, CEIDG, GUS, VAT systems or any other official Polish register.
Limitations
The validator only checks format and checksum. It does not confirm legal status, registration state, VAT activity, invoice eligibility or whether the company is currently operating.
Privacy note
The input is processed locally in your browser for the core validation result. The tool does not require an account and does not send the NIP to an API or business lookup service.
Last updated
Last updated: June 2026.
FAQ
What does a technically valid NIP mean?
A technically valid NIP means only that the format and checksum are valid according to the algorithm. It does not confirm business registration, does not confirm VAT status and does not query KAS, CEIDG, GUS or any official register.
Does this tool verify VAT status?
No. It does not query KAS, VIES, CEIDG, GUS or any official register. VAT status, business activity and registry details must be checked through the appropriate official source.
Can I use a NIP with PL prefix or hyphens?
Yes. The tool removes an optional PL prefix, spaces and hyphens before validation. The normalized result then shows the ten digits used for the checksum check.
Why can a technically valid NIP still be unusable?
Because checksum validation does not confirm registration or business status. A number can match the technical rule and still be inactive, revoked, unregistered or unrelated to the supplier you expected.
Related tools
You may also want to check these local validators and related work tools:
REGON Validator · Invoice Generator · Utility Tools · All Tools