Retention of accounting documents

If you are subject to the bookkeeping obligation, you must retain accounting documents in accordance with the relevant bookkeeping rules. There are no requirements regarding the format in which the documents must be stored. You can therefore decide whether you wish to keep vouchers on paper or in electronic format.


Primary documentation and secondary documentation

The Bookkeeping Act makes a distinction between primary and secondary documentation. Primary documentation is used as a basis for the actual bookkeeping process. Secondary documentation are often additional documentation with important information, which does not directly lead to any transactions in the accounts. Examples of secondary documentation include sales agreements, order slips and other agreements of importance for the enterprise.

In some cases, secondary documentation can also become be considered to constitute primary documentation because the primary documentation does not contain sufficient information. If you send an invoice with the following text: 'Sale in accordance with agreement', the agreement will be considered to be primary documentation and must be retained for the same period of time as the invoice.

Primary documentation must generally be retained for 5 years. The requirement for the retention of secondary documentation is 3.5 years.

Bokføringsloven om oppbevaring (in Norwegian only)

Bokføringsforskriften om oppbevaring (in Norwegian only)

NBS 1- sikring av regnskapsmateriale (in Norwegian only)

Retention of primary documentation - 5 years

The following are considered to be primary documentation:

  • Vouchers which form a basis for the actual bookkeeping (incoming and outgoing invoices, cash book balances, bank vouchers, salary slips, etc.)
  • Specification of mandatory financial reporting (account specification, customer and supplier specification, etc.)
  • Documentation of the balance sheet
  • Annual accounts and other mandatory financial reporting
  • Annual report
  • Audit report
  • Numbered letters from auditor

Retention of secondary documentation - 3.5 years

The following are examples of secondary documentation:

  • Agreements of importance to the business
  • Letters and other information which provide significant additional information for posted vouchers
  • Outgoing delivery notes and order slips
  • Price summaries which must be prepared in accordance with a law or regulation.
  • Staff register, where such registers are mandatory (e.g. hairdressing and restaurants and caf├ęs).

Some specific requirements - longer minimum retention period

Some sectors and transactions are subject to a longer minimum retention period. For example, project accounts in the construction and engineering sector and customer and supplier specifications in banks must be retained for ten years. Chapter 8 of the Bookkeeping Regulation gives an overview of additional provisions and special rules for the industries and sectors concerned.

Bokføringsforskriften - om tilleggsbestemmelser og særlige regler for enkelte næringer og bransjer (in Norwegian only)

Electronic retention

If you decide to retain your vouchers electronically, you must make back-up copies of the documents. You must at all times have an overview of the documents which you have back-up copies of and how often you make back-up copies. The summary must also state where the original and the back-up copies are kept.

Vouchers in the form of paper copies which you then scan and transfer to an electronic medium must be retained until you make a back-up copy. You can therefore not discard paper documents which have been scanned until you have made back-up copies of the scanned documents.

It is important that you store the vouchers in a way which will enable you to print them out on paper at any time during the statutory minimum retention period upon request.

Electronic availability

Bookkeeping information, which are stored electronically, must be available electronically for three years and six months after the end of the financial period.

NBS 3 - Elektroniske tilgjengelighet i 3,5 år (in Norwegian only)

Retention abroad

You can store electronic accounting documents in Denmark, Finland, Iceland and Sweden if you inform the Norwegian Tax Administration. You do not need to apply for permission to do this. This applies providing they are available electronically and can be printed out on paper in Norway at any time during the retention period. Paper-based accounting documents must be stored in Norway.

If you wish to store electronic accounting documents outside Norway, you must apply to the Norwegian Tax Administration for special permission to do this.

Oppbevaring i andre nordiske land (in Norwegian only)

Person responsible for storage

Even if you decide to allow others to store the vouchers for you, you will still be responsible for ensuring that they are stored in accordance with the relevant bookkeeping rules.

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