The advice is always "start fresh at the beginning of the financial year". Almost nobody does. People switch when the old thing finally becomes unbearable, which is a Tuesday in August, and by then there is a cash box, a bank account, a godown full of stock, customers who owe money and suppliers who are owed. All of that has to arrive in the new system somehow.
The instinct that causes the most damage
Re-entering everything. Every invoice since April, one at a time, so the new system "has the full history". It takes days, it introduces typing errors into records that were previously correct, and it produces a set of books that disagrees with the old set in ways nobody can reconcile later. The old system already has that history. Keep it, export it, and leave it alone.
What actually has to come across
Not the history. The position — where the business stood on the day you switched:
- Cash in hand.
- Bank balance.
- Stock, valued at what it cost you, not what you hope to sell it for.
- What each customer owes you.
- What you owe each supplier.
That is the whole list for most small businesses. Five numbers and two lists. Everything after the switch date the new system records itself.
Where the sixth number comes from
Add up what you have and subtract what you owe, and the difference is the owner's stake in the business. You do not look that number up anywhere — it is defined as the difference. Which is also why, in a properly kept set of books, the two sides always come out equal: one of the figures is whatever it has to be to make them equal.
If that sounds like a trick, it is not. It is the whole of double-entry bookkeeping in one sentence, and it is the reason an accountant can tell at a glance that something has been entered wrong.
The valuation that trips people
Stock at cost, not at selling price. Valuing stock at what you hope to get for it books a profit you have not made, inflates the owner's stake by the same amount, and makes every margin calculation for the rest of the year wrong in the same direction. It is the single most common opening-balance mistake and it is invisible afterwards — the books balance perfectly either way.
How this looks in BizGST Pro
One screen. Pick the date your books start, type cash, bank and stock, and fill in the customer and supplier lists. Underneath, the opening journal entry assembles itself as you type — Cash in Hand, Bank Account, Inventory, Receivables, Payables, and Owner's Capital as the balancing figure — with a total line that stays equal on both sides no matter what you change. The customer and supplier balances also seed the khata, the ageing report and the party ledger, so you enter them once.
A first attempt is not fatal
Posting the opening balances again replaces the previous opening entry rather than adding a second one. That matters more than it sounds: the fear of getting it wrong the first time is why a lot of businesses never finish the switch at all.
What this article does not cover
Anything about how a change of software must be reported, what records must be preserved and for how long, or how any of it is treated for tax. Those are set by rules that change and the sources are the GST portal and your accountant — we will not state them from memory. What is above is about your own books being right.