An account number is the unique numeric identifier banks use to identify individual bank accounts. In Norway, account numbers follow a standardised structure that guarantees unique identification across the banking system. Account numbers are essential for all bank transactions and play a critical role in bank reconciliation and bookkeeping.
Structure of Norwegian account numbers
Norwegian account numbers have a standard 11-digit structure regulated by the Financial Supervisory Authority and administered by Bits. This structure makes every account number unique and allows automatic validation.
Components
| Position | Digits | Description | Example |
|---|---|---|---|
| 1-4 | 4 | Bank code – identifies the bank | 1234 |
| 5-6 | 2 | Branch/group – identifies branch/department | 56 |
| 7-10 | 4 | Account sequence – unique within the bank | 7890 |
| 11 | 1 | Check digit – validates the account number | 1 |
Example: 1234.56.78901
- Bank: 1234 (e.g., DNB)
- Branch: 56
- Account: 7890
- Check: 1
Check digit and validation
The check digit is calculated using a modulus 11 algorithm to ensure the account number is valid. This prevents errors from manual entry and automates validation in payment systems .
Steps (simplified):
- Multiply each digit by its weight factor.
- Sum the products.
- Compute the modulus 11; the result determines the check digit.
- If the modulus check fails, the account number is invalid.
Link to IBAN
Account numbers form the domestic part of a Norwegian IBAN (15 characters). When you convert to IBAN, the country code (NO), check digits, bank code and account number are combined. IBAN validation uses Modulo 97, but relies on the underlying 11-digit account structure.
Best practice for businesses
- Validate account numbers on entry to avoid payment failures.
- Store verified account numbers for customers and suppliers to reduce re-entry mistakes.
- Use automated bank reconciliation to match account numbers with vouchers and statements.
- When sending international payments, always use the IBAN version of the account number together with BIC/SWIFT.