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REGON
Length
About Polish REGON numbers
Structure and types
REGON (Rejestr Gospodarki Narodowej) is a statistical identification number assigned by GUS (Central Statistical Office) to all business entities operating in Poland. It comes in two forms: 9 digits for the main entity and 14 digits for local units (branches) of the entity.
Checksum algorithm
The 9-digit REGON uses a modulo 11 checksum with weights [8, 9, 2, 3, 4, 5, 6, 7]. The 14-digit version applies an additional checksum with weights [2, 4, 8, 5, 0, 9, 7, 3, 6, 1, 2, 4, 8] to all 14 digits. In both cases, if the calculated remainder is 10, the check digit is 0.
Usage and verification
Every business entity registered in Poland receives a REGON number during registration. It is used for statistical reporting and appears in official business documents alongside NIP and KRS numbers. The REGON registry is maintained by GUS and can be queried through the BIR (Baza Internetowa REGON) online database to look up basic information about registered entities.
Use the validation API
All validators on this page are powered by our free REST API. Send a GET request with the number to validate and receive a structured JSON response with the validation result.
GET /api/v1/validate/regon/012100784
Host: polishdata.eu
// Response 200 OK
{
"valid": true,
"data": {
"regon": "012100784",
"length": 9
},
"errors": []
}