Why BAS sales do not match your profit and loss report

You'll need the profit and loss statement (P&L), the draft business activity statement (BAS), and the transaction detail behind both. Save a copy of each before making changes so you can show what explained the original difference.

Check what the two totals mean

G1 is the BAS total-sales label. It can include transactions outside ordinary trading revenue, such as a business asset disposal. GST reporting also follows the business's cash or non-cash basis. A standard accrual P&L usually shows trading revenue excluding GST, while the BAS may be prepared with GST-inclusive sales figures. Check the GST-included setting on the actual form and report.

The ATO instructions for completing the GST section of the BAS explain G1 and the reporting methods. Don't assume every figure labelled "sales" has the same scope. The P&L guide covers what the management report is measuring.

Build a bridge using gross amounts consistently

This fictional business has $50,000 of ordinary taxable revenue on its September-quarter accrual P&L. Its BAS uses cash accounting and GST-inclusive G1. All sales in the example are wholly taxable. There are no refunds or foreign-currency transactions, and the equipment disposal is absent from the selected trading-revenue line.

Step	Adjustment	Evidence
Accrual trading revenue	$50,000 starting amount	P&L sales-account detail
Add GST on that revenue	+$5,000 = $55,000	Invoice GST detail, not an assumed percentage on mixed sales
Remove this quarter’s unpaid invoices	-$11,000 = $44,000	Closing debtor list; all issued this quarter
Add receipts for earlier invoices	+$6,600 = $50,600	Bank matches and prior-quarter invoice references
Add paid taxable equipment sale	+$2,200 = $52,800	Disposal invoice and receipt; excluded from starting revenue
Expected cash-basis G1	$52,800	Compare with BAS sales transaction report

Each adjustment appears once. If a disposal gain is included in your starting P&L total, remove that gain before adding full relevant proceeds. Original ASBG worksheet; all example figures are fictional.

The explanation is $50,000 + $5,000 - $11,000 + $6,600 + $2,200 = $52,800. This arithmetic doesn't turn every real sale into a taxable one. GST-free, input-taxed and other transactions need their actual treatment, which the GST coding guide introduces.

Investigate the unexplained remainder

Suppose the BAS report instead shows $53,900. There is still $1,100 to explain. Search the detailed report for that amount, but also look for several entries that add to it. A duplicated receipt, an owner contribution coded as sales, or a payment allocated to the wrong invoice can all create a difference.

Match the transaction ID between reports. Descriptions and dates can be misleading when a bank receipt covers several invoices. Record whether an item is a timing difference, a difference in report scope or an actual error. Only the last category justifies a correcting entry.

Check report filters too: entity, date range, cash/accrual selection, sales accounts, tracking categories and archived accounts. An export taken before the final bookkeeping changes may simply be out of date.

Keep the explanation reproducible

For every adjustment, save the source document, ledger ID, gross and GST amounts, explanation and reviewer decision. Include the report run date. A note saying "timing" without the invoices behind it leaves the same problem for next quarter.

If the BAS was already lodged, separate investigating the difference from deciding how to correct it. Changing a historical transaction can alter the current report without changing the lodged BAS. Give your agent both versions and the proposed correction. The lodgement guide explains where reporting fits into the process.

Continue with the next question

• Cash or accrual GST accounting: compare the timing
• Unexpected BAS refund? Check the figures before lodging

Key takeaways

• Align dates, basis and GST display before comparing totals.
• Explain timing and asset disposals with transaction-level evidence.
• Keep investigating unexplained differences instead of forcing revenue to match G1.

Where to get help

Start with the ATO BAS instructions. Ask your registered agent to check unusual sales and the finished bridge. Find the related records and reporting guides in Bookkeeping and BAS.