What is a Swedish organisationsnummer?

It is the 10-digit registration number the Swedish Companies Registration Office (Bolagsverket) or Skatteverket assigns to legal entities such as limited companies, associations and authorities. It is written as six digits, a hyphen, then four digits.

How is the check digit calculated?

The last digit is a Luhn (mod-10) check over the first nine digits: double every second digit from the right, sum the digits of the products plus the untouched digits, and the check digit makes the total a multiple of 10.

Why must the third digit be at least 2?

In an organisationsnummer the third digit is 2 or higher. This is what separates a company number from a personnummer, whose digits encode a real calendar month and so cannot use that range in the same position.

Does a valid number mean the company is active?

No. A passing Luhn check confirms the number is well-formed, not that the entity is currently registered or trading. Check Bolagsverket or allabolag.se for live status.

Is my number sent anywhere?

No. The validation runs entirely in your browser; the number never leaves your device.

Sweden Organisationsnummer Validator

A Swedish organisationsnummer is the 10-digit identifier assigned to every legal entity in Sweden — limited companies, economic associations, foundations and public bodies. It appears on invoices, contracts and the company register. This free validator confirms its structure, Luhn check digit and company-marker rule in your browser.

How it works

Length. Exactly 10 digits, written NNNNNN-NNNN.
Company marker. The third digit must be 2 or higher — the rule that distinguishes an organisationsnummer from a personnummer.
Luhn check. The 10th digit is a mod-10 Luhn check over the first nine:
- Starting from the rightmost of the first nine digits, double every second digit.
- If a doubled value exceeds 9, subtract 9 (equivalently, add its digits).
- Sum all the values; the check digit is the amount needed to reach the next multiple of 10.

Example

556036-0793: the third digit is 6 (≥ 2, so the company marker passes), and running Luhn over 556036079 yields a check digit of 3, which matches the final digit — so the number is valid.

Notes

A valid number is internally consistent, not necessarily an active company. For registration status, consult Bolagsverket. Everything here runs locally, so your data stays on your device.