Rejestr Gospodarki Narodowej
Poland · Companies
Paste or type the number — punctuation is optional.
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What this check does — and what it cannot do
This tool checks the number's structure and its check digit, using the published algorithm for that document. A number that passes is well formed: it is arithmetically consistent and could have been issued.
It cannot tell you whether the number was actually issued, whether it is active, or who it belongs to. Only the issuing tax authority can confirm that, through its own lookup service. Treat a passing result as "worth submitting", never as proof of identity.
The generator produces numbers that satisfy the same checksum, for filling forms while developing and testing software. They are arithmetic, not records: they are not drawn from any register and do not correspond to a real holder. No generator is offered for the US Social Security Number.
Calculated in your browser. Nothing you enter is sent anywhere.
A 14-digit REGON has to pass two checksums, not one
The nine-digit REGON identifies the legal entity. The fourteen-digit form identifies one local unit of that entity, and it is not a fresh number — its first nine digits are the parent REGON and must still satisfy their own check digit, while the fourteenth digit checks the whole string against a different set of weights.
How it works
- Checks the ninth digit with the weights 8 9 2 3 4 5 6 7.
- For a 14-digit number, additionally checks the fourteenth with 2 4 8 5 0 9 7 3 6 1 2 4 8.
- Says whether the number is the entity itself or one of its local units.
9-digit: check = (Σ weightᵢ × digitᵢ mod 11) mod 10, weights 8 9 2 3 4 5 6 7
14-digit: the first nine must still pass the above,
and check₁₄ = (Σ weightᵢ × digitᵢ mod 11) mod 10 over digits 1-13Worked example
Why both tests matter.
- the first nine digits name the company and carry their own check digit
- digits 10 to 13 identify which branch, shop or site
- the fourteenth digit checks all thirteen that precede it
- a 14-digit number whose first nine fail is not a unit of any real entity
- the remainder 10 is mapped to 0 rather than making the prefix unusable
A hierarchical identifier where the parent is embedded in the child. Truncating a 14-digit REGON to nine digits gives you the company it belongs to.
Reading the result
- REGON is not NIP. REGON comes from the statistical office and identifies the entity for registry purposes; NIP is the tax number. Polish forms often ask for both, and they are not derivable from one another.
- Unlike NIP, a remainder of 10 is folded to 0 rather than making the prefix unusable. That is a different trade against the same modulo-11 problem, and it means REGON loses a little error-detection strength in exchange for using the whole number space.
- A generator is offered because this identifies an organisation rather than a person, and populating a test system with well-formed registry numbers is ordinary work.
Common questions
- I have a 14-digit REGON — what are the first nine digits?
- The REGON of the parent entity. The longer form is built by appending a four-digit unit number and a check digit, so the company's own number is still sitting there at the front.
- Does a valid REGON mean the business is active?
- No. It means the digits are internally consistent. Entities that have been wound up keep their number, so the register is the only place to check current status.