Poland REGON validator
How the REGON format works
- Format
- 9 digits (business entity) or 14 digits (local unit: the parent's 9-digit REGON + 4-digit unit number + check digit)
- Example
- 610188201
Things to watch for
- A 14-digit REGON identifies a local unit (branch) — both its own last digit and the embedded 9-digit parent REGON must pass
- REGON is a statistical number issued by GUS and is different from the NIP tax number — a company has both
- Checksum only — a pass doesn't confirm the entity is listed in the REGON register
^([0-9]{9}|[0-9]{14})$REGON is the statistical identification number that Statistics Poland (GUS, Główny Urząd Statystyczny) assigns to entities in the national business register, the Krajowy Rejestr Urzędowy Podmiotów Gospodarki Narodowej. Companies, sole traders, public bodies and other organisations all have one. It comes in two lengths: 9 digits for the entity itself, and 14 digits for each local unit that’s registered separately.
The 9-digit check
The final digit comes from weights 8, 9, 2, 3, 4, 5, 6, 7 applied to the first eight digits. The sum is divided by 11, and the remainder is the check digit, except that a remainder of 10 becomes 0. For the example 610188201, the weighted sum is 144 and the remainder is 1, which matches the last digit.
Two checks for a 14-digit number
A 14-digit REGON is the parent’s 9-digit REGON, then a 4-digit unit number, then a new check digit. The new check digit is calculated over the first 13 digits with weights 2, 4, 8, 5, 0, 9, 7, 3, 6, 1, 2, 4, 8. The fifth weight is 0, so that digit has no effect on the long check. The embedded 9-digit REGON matters here: its own check digit is the only one that can catch a typo in the fifth digit. This tool runs both checks and fails the number if either one fails.
What a pass doesn’t tell you
A pass confirms the digits are consistent. It doesn’t show that the entity or unit is in the REGON register, active or still trading. Tax matters use a different number, the NIP, which has its own mod-11 check. You can check it with the Poland NIP validator.
Scope: REGON format and checksum validation only. It doesn’t cover register status.
Content last reviewed 2026-10-11.
REGON FAQ
What's the difference between a 9-digit and a 14-digit REGON?
A 9-digit REGON identifies the entity itself, such as a company, sole trader or other organisation. A 14-digit REGON identifies one of its local units, such as a branch. It starts with the parent's 9 digits, adds a 4-digit unit number, and ends in its own check digit.
Why would a 14-digit REGON fail when its last digit looks right?
Both checks must pass. The first nine digits have to be a valid REGON on their own, and the whole number has to satisfy the 13-weight formula. A typo in the fifth digit, which has a weight of 0 in the 14-digit formula, can only be caught by the 9-digit check.
Do sole traders in Poland have a REGON?
Yes. Sole traders running a registered business are entered in the REGON register and receive a 9-digit number, just like companies. This tool validates it with the same 9-digit formula, and a valid checksum still doesn't show whether the business is active.