How long do accounting records have to be kept?
Core accounting documentation has to be kept for five years after the end of the financial year, and some supporting documentation for three years and six months. Some areas have longer requirements: construction has ten years for project accounts, and VAT adjustment on real property can require around fifteen. From 1 January 2027 structured e-invoicing becomes mandatory, and from 1 January 2030 the requirement for an electronic accounting system.
The main rules: five years and three and a half
Core accounting documentation: five years after the end of the financial year. Some supporting documentation: three years and six months after the end of the financial year. You cannot delete old records because the tax return has been filed. A business subject to bookkeeping obligations has to keep the material so that the bookkeeping and the reporting can be checked later.
What is kept for five years?
Typically the annual accounts and other mandatory reporting, bookkeeping specifications, invoices and credit notes, payroll records, bank documentation, documentation of balance sheet items, and stock count documentation. That is the core: everything showing what was booked and why.
What is kept for three and a half years?
Certain agreements, correspondence, packing notes, statutory price lists and timesheets under particular rules. But there is an important qualification: where the supporting documentation is necessary to understand the record itself, it may have to be kept longer. An agreement explaining what an invoice covers can in practice follow the invoice's deadline.
Timesheets and project accounts
Ordinary timesheets do not automatically carry a five-year retention period – documentation under certain provisions has three and a half years. Construction, by contrast, has special rules with ten years' retention for project accounts and specified documentation. Where the business is in construction, that is the deadline that applies – and it is twice the general rule. See also A labour crime inspection on site
Real property and VAT: around fifteen years
Documentation relating to VAT adjustment for real property may have to be kept for around fifteen years from the year of completion. The arithmetic: the adjustment period is ten years, and the documentation is kept for five years after the last adjustment year. For a construction measure completed in 2026 that means documentation until 2040 – see The VAT adjustment rules for real property That is the longest retention period most businesses meet, and it has to go into the routine at completion. Not be discovered in year nine.
Requirements for the storage itself
Accounting records have to be organised, accessible, legible, secured against loss and destruction, protected against unauthorised change, and capable of being produced on an audit. Paper documentation can be scanned where verifiability is not weakened. But the paper should not be destroyed before the electronic copy has been checked and backed up.
Storage abroad
Electronic accounting records can be kept in other EEA countries, the United Kingdom and Switzerland under the current rules. The business has to inform the tax office about the storage and make sure the material is accessible from Norway. If you use a cloud service, it is worth knowing where the data actually sits – not just who provides the service.
Changing systems
On a change of accounting system, historical documentation still has to be legible and verifiable. That can be solved with read access to the old system, data migration, or a separate electronic archive. There is no general requirement to buy an old read licence where the material is otherwise kept correctly. That is a claim suppliers sometimes make on termination. What has to be secured before the old subscription ends is in Changing accounting system
SAF-T
SAF-T is a standardised format for exporting accounting data. The file is not submitted annually, but can be required on an audit. Nor does a SAF-T file necessarily replace invoice images, agreements and other mandatory documentation. Having SAF-T in order is not the same as having met the retention obligation. Note too that the format changes: SAF-T Financial 1.40 becomes the only valid version for new periods from 1 January 2027. Version 1.30 can be used until 31 December 2026.
The retention duty survives the winding up
The duty does not disappear when the business is wound up. For a limited company the board has to make sure the material is still kept. Company documentation also has its own ten-year requirements. It is worth settling who actually holds the archive before the company is deleted – see VAT on winding up and bankruptcy
New rules in two stages: 2027 and 2030
The Act of 19 June 2026 no. 39 on mandatory digital bookkeeping and e-invoicing comes into force in stages. From 1 January 2027 the first phase of mandatory structured B2B e-invoicing applies. A PDF is not a structured e-invoice – the Act defines an electronic invoice as a sales document that can be issued, sent and received in a structured format. Electronic invoices have to be kept in their original structured format. From 1 January 2030 the requirement that bookkeeping be done in an electronic accounting system comes into force. So it is wrong to say every business has to use an electronic accounting system from 2027. The two requirements are three years apart, and it is worth keeping them separate when suppliers are selling upgrades.
In short
Five years for core documentation. Three and a half years for some supporting documentation. Ten years or more under certain special rules. E-invoicing phased in from 2027, and mandatory electronic accounting systems from 2030. If you need the archive in order, we can set up retention routines, handle a system change and check the accounting documentation.
Read more
This is general guidance, not advice on your specific case. Deadlines, rates and amounts change – always check the current rules, or get in touch with us.
More on year-end close and reporting
- What has to be done in the year-end close for a company and a sole trader?
- Statutory audit – when can an AS opt out of an auditor?
- The tax return for businesses – how does it differ from a personal one?
- The shareholder register statement – deadline, content and errors
- Depreciation – which groups and rates apply?
- Inventory at the year-end close – how is it counted and valued?
- Why is the result not the same as the money in the account?
- The annual cycle for a Norwegian AS – which deadlines apply through the year?
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