The organization number
Every entity that is registered in the Central Coordinating Register of Legal Entities is given an organization number. The organization number identifies legal entities etc. and is the key to the information about them in the Brønnøysund registers. Enterprises registered in the Central Coordinating Register of Legal Entities must see to it that the organization number is printed on their business documents.
Construction of the Norwegian organization number
The organization number consists of 9 digits, where the last is a check digit calculated by weighting the individual digits with standard weights, modulus 11. According to this, the weights 3, 2, 7, 6, 5, 4, 3 and 2 are assigned to each digit.
Modulus 11
Example:
Number without check digit: 
1 
2 
3 
4 
5 
6 
7 
8 

Weights: 
3 
2 
7 
6 
5 
4 
3 
2 

Products: 
3 
+ 
4 
+ 
21 
+ 
24 
+ 
25 
+ 
24 
+ 
21 
+ 
16 
= 
138 
Division: 
138 
: 
11 
= 
12 with a remainder of 6 

Check digit: 
11 
 
6 
= 
5 



Number with check digit: 
1 
2 
3 
4 
5 
6 
7 
8 
5 
The digits in the field is multiplied with the weights 2, 3, 4, 5, 6, 7, 2, 3 starting from the right. The sum of products (in this case 138) is divided by 11. The remainder from the division (in this case 6) is subtracted from 11 and the result is the check digit (in this case 5). If there is no remainder (remainder = 0), the check digit is 0. If the check digit is 10 (remainder = 1), the check digit must be replaced with a  (minus).
 (minus) is not a valid check digit for the organization number.