Definition
Opening balances are the account balances a business carries into a new system or financial year, so its books start from the correct position.
Opening balances meaning when you change system
When you move to a new accounting system, you bring in balances at a chosen cutover date instead of re-entering years of history. That usually means an opening trial balance for the ledger, plus the detail behind key accounts: open customer invoices, unpaid supplier bills, and stock quantities with their costs. The detail must add up to the control account balances, and the trial balance must balance.
Example: at cutover, a trader brings in USD 320,000 of stock across 4,300 lines, USD 230,000 of receivables and a balanced trial balance.
Opening stock is usually counted physically at cutover.