🇳🇴Norwegian Organisation Number (Organisasjonsnummer) Validator

Organisasjonsnummer validator — check a Norwegian organisation number

Our free organisasjonsnummer validator instantly verifies the correctness of a Norwegian organisation number (org.nr.). The tool ignores spaces, checks that the number is exactly 9 digits, and then validates the check digit using the MOD-11 algorithm used by the Norwegian Brreg register (Brronnysundregistrene).

If you issue invoices for Norwegian companies, import counterpart data, or check commercial documents, this validator will help you quickly catch typos. Keep in mind that a valid check digit only confirms that the number is mathematically consistent — it does not verify whether the company is currently registered.

Full privacy — local processing

All validation takes place entirely in your browser. Not a single digit of the entered number is sent to any server. You can use the validator offline as well.

Frequently asked questions

What is an organisasjonsnummer?

An organisasjonsnummer (org.nr.) is a Norwegian 9-digit identification number assigned to entities registered with Brreg (Brronnysundregistrene). It identifies companies, associations, and other organisations in the Norwegian administrative and tax system.

How does the MOD-11 check digit validation work?

The first 8 digits of the number are multiplied by the weights [3, 2, 7, 6, 5, 4, 3, 2], the results are summed, and the remainder from dividing by 11 is calculated. The check digit is 11 minus that remainder. If the result is 11, the check digit is 0. If the result is 10, the number is inherently invalid — no single-digit check digit exists for that sum.

Where can I look up a company by its organisasjonsnummer?

The official register is maintained by Brreg (brreg.no). By entering a valid organisasjonsnummer you can look up the company name, address, legal form, and status (active/dissolved). Our validator only checks the mathematical correctness of the check digit and does not connect to the register.

Is an organisasjonsnummer the same as a D-nummer?

No. An organisasjonsnummer identifies organisations and companies. A D-nummer is a temporary identification number assigned to individuals who are not entitled to a Norwegian personal number (fodselsnummer). Both have 9 digits but serve different purposes and use different validation schemes.

Is my data sent to a server?

No. All validation takes place locally in your browser — not a single digit of the entered number reaches any server. You can validate numbers even without an internet connection.