GST Reconciliation Generator

Why Reconcile Your GST Accounts Before Lodging?

A GST reconciliation is the process of agreeing the GST balances in your general ledger (GL) to the amounts reported on your Business Activity Statement. Before lodging a BAS, your accountant or bookkeeper should confirm that the GST Collected account in the GL matches label 1A on the BAS, and that the GST Paid (or Input Tax Credits) account matches label 1B. Any difference — or variance — must be explained and resolved before lodgement, otherwise you risk under-reporting or over-claiming GST, both of which can attract ATO scrutiny, penalties, and interest.

Common causes of a GST reconciliation variance include: transactions coded to the wrong GST tax code, credit notes or adjustments posted in the GL but not reflected on the BAS, timing differences where invoices straddle two BAS periods, bank feed transactions with missing or incorrect GST treatment, and manual journal entries that bypass GST coding. Using a structured reconciliation template forces you to document your GL balance, list any known adjustments, and calculate the adjusted figure for comparison to each BAS label. This creates a clear audit trail and makes it easy to spot the source of any variance before it becomes an ATO problem.

Businesses that process high volumes of supplier invoices — particularly in industries like construction, manufacturing, and field services — are most at risk of GST coding errors accumulating across a quarter. A single miscoded invoice (for example, a taxable supply coded as GST-free) understates both label 1A and 1B and may not be obvious until the reconciliation is performed. Running a GST reconciliation at the end of each month, rather than waiting until the BAS is due, significantly reduces the risk of a large unexplained variance at quarter end.

How to use this GST reconciliation generator

1. Pull your GST Collected and GST Paid account balances from your accounting software's trial balance or GST detail report for the BAS period.
2. Enter those GL balances into the tool, then add any known adjustments — such as credit notes processed after period end, reclassifications, or timing differences — using the adjustment rows.
3. Enter the 1A and 1B amounts from your draft BAS or accounting software's BAS report. The tool calculates the variance between the adjusted GL balances and the BAS figures.
4. If the variance is nil, your GST accounts reconcile and the BAS can be lodged with confidence. If a variance exists, investigate and resolve it before lodging — download the PDF to attach to your workpapers or share with your BAS agent.

What does label 1A and 1B mean on the BAS?

Label 1A is the total GST collected on your taxable sales during the period — this corresponds to your GST Collected (or GST Output) account in the GL. Label 1B is the total GST credits you are claiming on business purchases — this corresponds to your GST Paid (or GST Input) account. The net of 1A minus 1B is the GST amount payable to the ATO (or refundable if 1B exceeds 1A). Both figures must agree to your accounting records before lodgement.

How do I find the GST variance?

Start with your accounting software's GST detail report filtered to the BAS period. Compare each transaction against the GL account. Common sources of variance are: bank feed transactions auto-coded with the wrong GST type, purchase invoices over AU$82.50 without a valid tax invoice (meaning the credit cannot be claimed), transactions coded to the wrong entity or period, and manual journals posted without GST treatment. Xero's "GST Audit Report" and MYOB's "Tax Code Detail" report are useful starting points.

Do I need to keep a copy of the GST reconciliation?

Yes. The ATO requires businesses to keep records that explain and support the amounts reported on each BAS for a minimum of five years. A completed GST reconciliation is a key workpaper — it demonstrates that the figures on the BAS were verified against the GL before lodgement. If the ATO reviews or audits your GST, having a clear reconciliation for each period will significantly reduce the time and cost of responding. Download the PDF from this tool and store it alongside your BAS confirmation and accounting reports for each quarter.

What if I find an error after the BAS has already been lodged?

If you discover a GST error after lodgement, you can correct it on a future BAS if the net GST error is AU$10,000 or less (or within certain percentage thresholds). For larger errors, you must revise the original BAS by contacting the ATO or using the online services portal. Voluntarily disclosing an error — rather than waiting for the ATO to find it — generally results in reduced penalties and interest. Your registered BAS agent or tax agent can assist with the amendment process.