BAS Lodgement Step-by-Step Guide
Complete guide to lodging your Business Activity Statement (BAS) with the ATO. GST labels G1–G20 explained, PAYG withholding, due dates, and Simpler BAS vs Full BAS.
How to Lodge Your BAS — 7 Steps
From ATO login to payment — complete walkthrough.
Log in to ATO Business Portal or myGov
Use your myGovID (Relationship Authorisation Manager for businesses) or log in through your registered tax agent's software. Sole traders can use their personal myGov linked to ATO.
Select your BAS period
Choose the correct reporting period — quarterly (most common) or monthly. The ATO pre-fills some amounts if you've linked bank feeds. Verify pre-filled data before proceeding.
Report GST (Labels G1–G20)
Enter your sales and purchase figures. If using Simpler BAS (turnover < $10 million), you only need G1 (total sales), 1A (GST collected), and 1B (GST paid). Full BAS requires all G1–G20 labels.
Report PAYG Withholding (Labels W1–W5)
W1 = Total salary/wages and other payments. W2 = Amounts withheld from payments (tax withheld from employees). W3 = Withheld from investment distributions. W4 = Withheld where no ABN quoted.
Report PAYG Instalments (Label T7–T9)
If you pay tax by instalments, enter your instalment amount (T7) or calculate from your instalment rate × instalment income. T8 = Estimated net tax for the year. T9 = Varied amount.
Review & Lodge
Review the summary showing net GST (1A – 1B), PAYG withholding (W2+W3+W4), and PAYG instalments. The total amount owing or refundable is calculated. Submit electronically via the portal.
Pay or Receive Refund
If you owe, pay by the due date via BPAY, direct debit, or credit card. Refunds are typically processed within 14 days for electronic lodgement. Payment plans available if you can't pay in full.
BAS GST Labels — G1 to G20 Explained
Full BAS requires these labels. Simpler BAS only needs G1, 1A, and 1B.
| Label | Description |
|---|---|
| G1 | Total sales (including GST) |
| G2 | Export sales |
| G3 | Other GST-free sales |
| G4 | Input taxed sales |
| G5 | G2 + G3 + G4 total |
| G6 | Total sales subject to GST (G1 – G5) |
| G7 | Adjustments |
| G8 | Total GST on sales (G6 ÷ 11 + G7) |
| G9 | Total GST on sales |
| G10 | Capital purchases (including GST) |
| G11 | Non-capital purchases (including GST) |
| G12 | G10 + G11 total |
| G13 | Purchases for making input taxed sales |
| G14 | Purchases without GST in the price |
| G15 | Estimated purchases for private use |
| G16 | G13 + G14 + G15 total |
| G17 | Total purchases subject to GST (G12 – G16) |
| G18 | Adjustments |
| G19 | Total GST on purchases (G17 ÷ 11 + G18) |
| G20 | Total GST on purchases |
Quarterly BAS Due Dates — 2026
Standard quarterly lodgement schedule. Monthly lodgers must submit by the 21st of the following month.
| Quarter | Due Date |
|---|---|
| July – September (Q1) | 28 October |
| October – December (Q2) | 28 February |
| January – March (Q3) | 28 April |
| April – June (Q4) | 28 July |