How to switch accounting system

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 April or 1 January, depending on your year-end) is strongly recommended so you can start with an opening balance and no history in the new system.
  • Start of a VAT period for VAT-registered businesses (quarterly: Jan-Mar, Apr-Jun, Jul-Sep, Oct-Dec; or monthly if applicable).
  • Month-end if you do not file VAT. Avoid switching mid-period when you have many transactions.

Preparations (checklist)

  1. Reconcile the accounts in the old system up to the switch date (bank, customers, suppliers, VAT, payroll if relevant).
  2. Lock the period up to the switch date so figures cannot change afterwards.
  3. Export data:
    • Full data export (CSV, Excel or backup file – format varies by system).
    • Trial balance as of the switch date (CSV/PDF) – used to post the opening balance.
    • Receipts and 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 return.
  • 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 transactions from two systems in the same period.

Using the trial balance to start in the new system

  1. Obtain the trial balance as of the switch date from the old system.
  2. Post the opening balance in the new system with the same chart of accounts (or map accounts if you change chart).
  3. Check that total assets = total equity and liabilities (the balance is zero).
  4. Enter outstanding customer and supplier balances if you want to track open items.

Receipts and documentation

  • Download all attachments from the old system. Store them securely (HMRC record-keeping rules require this).
  • In the new system you can upload attachments for new transactions. Historical attachments can be stored externally but should be searchable.

Retention of accounting records

When you change system you must follow HMRC rules for retaining business records. In short:

  • Retention: At least 6 years after the end of the relevant tax year (longer for some items, e.g. Companies House records).
  • What counts as records: receipts, invoices, bank statements, posted entries (general ledger, sub-ledgers), trial balance, contracts, etc.
  • Format: May be stored electronically (scanned/exported) but must be complete, readable and traceable.
  • Storage and access: Must be securely stored with backup routines for HMRC inspections.
  • At system change: Ensure continued access to historical data and attachments for the whole retention period (export reports and attachments before closing the old system).

Step-by-step process

  1. Decide the switch date and lock the period in the old system.
  2. Export: data backup, trial balance, customers/suppliers and attachments.
  3. Create the company in the new system and verify chart of accounts/VAT codes.
  4. Post the opening balance from the trial balance (as of the switch date).
  5. Import customers/suppliers and any products.
  6. Set up bank integration and test in/out payments. Read more about bank integration via ZTL .
  7. Post the first transaction in the new system and verify reports (general ledger, balance sheet, profit and loss, VAT if relevant).

Common pitfalls

  • Different chart of accounts or VAT codes not mapped correctly.
  • Open customer/supplier items not entered at transition.
  • Transactions missing attachments – make sure documentation is archived and accessible.
  • Switching mid VAT period without a clean reconciliation beforehand.

Summary

Plan the switch date, lock and reconcile the old system, export your data and the trial balance, post the opening balance in the new system, and continue bookkeeping there. That makes the transition both efficient and safe.