This guide shows how to change accounting system in a tidy, low-risk way. It applies no matter which system you come from. See also the comparison ReAI vs. other accounting systems .
When is it easiest to switch?
- New financial year (1 January) is strongly recommended so you can start with an opening balance and no history in the new system.
- Start of a VAT period (Jan-Mar, Apr-Jun, Jul-Sep, Oct-Dec) for VAT-registered businesses.
- Month-end if you do not file VAT. Avoid switching mid-period when you have many vouchers.
Preparations (checklist)
- Reconcile the accounts in the old system up to the switch date (bank, customers, suppliers, VAT, payroll if relevant).
- Lock the period up to the switch date so figures cannot change afterwards.
- Export data:
- SAF-T Finance (standard format for transactions, chart of accounts, customers/suppliers, etc.).
- Trial balance as of the switch date (csv/pdf) – used to post the opening balance.
- Vouchers/attachments (PDF/JPG/PNG) – keep them in a monthly folder structure.
- Customers and suppliers (CSV/Excel) – useful if you want to import master data separately.
- Products/items (optional) – helpful for continued invoicing.
VAT periods and reporting
- Close the VAT period in the old system: reconcile, lock and save the VAT report.
- Post any VAT corrections in the old system before you switch.
- Start a new VAT period in the new system after the switch date. Do not mix vouchers from two systems in the same period.
Using the trial balance to start in the new system
- Obtain the trial balance as of the switch date from the old system.
- Post the opening balance in the new system with the same chart of accounts (or map accounts if you change chart).
- Check that total assets = total equity and liabilities (the balance is zero).
- Enter outstanding customer and supplier balances if you want to track open items.
Vouchers and documentation (PDFs)
- Download all attachments from the old system. Store them securely (bookkeeping rules require this).
- In the new system you can upload attachments for new vouchers. Historical attachments can be stored externally but should be searchable.
Retention of accounting records (Altinn)
When you change system you must follow the rules for retaining accounting records. In short:
- Retention: At least 5 years after the end of the financial year (longer for some documentation).
- What counts as accounting material: vouchers/attachments, booked entries (general ledger, sub-ledgers), trial balance, agreements, etc.
- Format: May be stored electronically (scanned/exported) but must be complete, readable and traceable.
- Storage and access: Must be securely stored with backup/availability routines for inspections.
- At system change: Ensure continued access to historical data and attachments for the whole retention period (export SAF-T, reports and attachments before closing the old system).
For detailed and updated requirements, see Altinn’s guidance:
https://info.altinn.no/starte-og-drive/regnskap-og-revisjon/regnskap/oppbevaring-av-regnskapsmateriale/
Step-by-step process
- Decide the switch date and lock the period in the old system.
- Export: SAF-T, trial balance, customers/suppliers and attachments.
- Create the company in the new system and verify chart of accounts/VAT codes.
- Post the opening balance from the trial balance (as of the switch date).
- Import customers/suppliers and any products.
- Set up bank integration and test in/out payments. Read more about bank integration via ZTL .
- Post the first voucher in the new system and verify reports (general ledger, balance sheet, income statement, VAT if relevant).
Common pitfalls
- Different chart of accounts or VAT codes not mapped correctly.
- Open customer/supplier items not entered at transition.
- Vouchers missing attachments – make sure documentation is archived and accessible.
- Switching mid VAT period without a clean reconciliation beforehand.
What is SAF-T?
SAF-T is a standard format (XML) for exchanging accounting data between systems and for audits. When you export SAF-T from the old system, the new system can read key data, or you can use the file as documentation of history.
Summary
Plan the switch date, lock and reconcile the old system, export SAF-T and the trial balance, post the opening balance in the new system, and continue bookkeeping there. That makes the transition both efficient and safe.