Before you start
Run the GST Audit Report first. It flags the most common pre-lodgement errors:
- Invoices coded Standard with $0 GST
- Off-band GST rates (anything that is not 0%, 10% or marked GST-free)
- Bills with tax codes that conflict with the account type
- Period locks not in place
Fix any flagged items before lodging. Once lodged, fixing them requires a revision — much more painful.
The fields
Sales side
- G1 — Total sales (including GST): the sum of all customer invoices issued in the period, GST-inclusive. Includes GST-free and export sales.
- G2 — Export sales: subset of G1 that is genuinely exported.
- G3 — Other GST-free sales: subset of G1 that is GST-free for domestic reasons (basic food, certain medical, education).
- 1A — GST on sales: the 10% GST collected. Equals G1 minus G2 minus G3, all divided by 11.
Purchases side
- G10 — Capital purchases (including GST): bills against asset accounts (anything in your fixed-asset register or capitalised).
- G11 — Non-capital purchases (including GST): every other deductible bill, GST-inclusive.
- 1B — GST on purchases: 10% GST credit on G10 + G11, divided by 11.
Payroll side
- W1 — Total salary, wages and other payments: gross wages from STP-reported pay runs.
- W2 — Amount withheld: PAYG withheld from those wages.
Payment
- 5A — PAYG instalment amount: from your PAYG Installments page for the quarter (either T7 or T1×T2).
The summary at the bottom computes: 1A − 1B + W2 + 5A = your net payment to the ATO (or refund if the figure is negative).
Lodging
From the BAS page, click Mark as lodged once you have lodged via the ATO Business Portal (or your tax agent has done it for you). You will be asked for:
- The lodgement date
- The ATO receipt number
- The net amount
OneBookPlus records this as a frozen snapshot — the figures are immutable from this point. The corresponding journal (the GST settlement) is posted when you record the payment via the GST Settlement action.
Revising a lodged BAS
If you spot an error after lodgement, the ATO requires a revision rather than overwriting the original. From the BAS Lodgements page, open the lodged record and click Create revision. This creates a new snapshot with the corrected figures, leaves the original in place for audit, and posts a top-up or refund journal for the difference.