If you are registered for GST you have to lodge a Business Activity Statement. It looks intimidating because it is a government form covered in code numbers, but the codes are just labels for totals you already have in your books. This guide walks through the ones a small business actually fills in.
What a BAS is for
A BAS does two jobs at once. First, it reconciles GST: you collected GST on your sales, you paid GST on your purchases, and the difference is either owed to the ATO or refundable to you. Second, it reports amounts you withheld on behalf of someone else — most commonly PAYG withholding from employee wages.
The form you receive depends on what you are registered for. A sole trader registered for GST with no employees fills in a handful of G-labels and nothing else. An employer also fills in the W-labels. Nobody fills in all of it.
The labels, in plain language
These are the labels Ledgable pre-fills, and what each one is a total of.
| Label | Name on the form | What goes in it |
|---|---|---|
| G1 | Total sales | Everything you sold in the period, GST included. This includes GST-free sales, not just taxable ones. |
| G2 | Export sales | The part of G1 that was exported. Exports are GST-free. |
| G3 | Other GST-free sales | The rest of your GST-free sales — basic food, most health and education services. |
| G10 | Capital purchases | Things you bought that are assets rather than running costs: a vehicle, machinery, a computer. |
| G11 | Non-capital purchases | Ordinary business purchases — stock, rent, subscriptions, fuel. GST included. |
| 1A | GST on sales | The GST you actually collected. This is the amount you owe. |
| 1B | GST on purchases | The GST you actually paid and can claim back. |
The number that matters is 1A minus 1B. If it is positive you pay the ATO; if it is negative you are due a refund.
If you have employees
| Label | Name on the form | What goes in it |
|---|---|---|
| W1 | Total salary, wages and other payments | Gross wages for the period, before tax. |
| W2 | Amounts withheld from payments shown at W1 | The PAYG tax you withheld from those wages. |
| W5 | Total amounts withheld | W2 plus any other withholding — for example where a supplier did not quote an ABN. |
Superannuation is not on the BAS. Super is paid to employees' funds, not to the ATO, and it runs on its own deadline — which changed on 1 July 2026. See Payday Super from 1 July 2026.
How often you lodge, and when it is due
Your reporting cycle is set by your GST turnover, and the ATO tells you which one you are on.
| Cycle | Who it applies to | Due date |
|---|---|---|
| Monthly | Compulsory if your GST turnover is $20 million or more. You can also elect it voluntarily. | The 21st of the following month. A July BAS is due 21 August. |
| Quarterly | Most small businesses: GST turnover under $20 million, unless the ATO has told you to report monthly. | Q1 Jul–Sep: 28 October · Q2 Oct–Dec: 28 February · Q3 Jan–Mar: 28 April · Q4 Apr–Jun: 28 July |
| Annually | Voluntarily registered for GST with turnover under $75,000. | 31 October, as an annual GST return rather than a BAS. |
If a due date lands on a weekend or a public holiday, you have until the next business day. Lodging through a registered tax or BAS agent usually earns you an extension on most quarters, though not on the February one.
Cash or accruals: which basis you report on
On a cash basis you account for GST in the period the money actually moves. On an accruals basis you account for it when you issue or receive the invoice, regardless of when it is paid. Businesses with aggregated turnover under $10 million can choose cash accounting for GST; above that, accruals is the default.
For a small business with slow-paying customers, cash basis is usually kinder to cash flow: you do not hand the ATO GST on an invoice you have not been paid for yet. The trade-off is that your BAS and your profit and loss will tell slightly different stories — see How to read a profit and loss statement.
Preparing a BAS without dreading it
Almost all BAS pain is the same problem: three months of uncategorised transactions, all landing at once, a week before the deadline. The fix is not working faster in that week. It is making sure the categorisation happens continuously.
A BAS that takes twenty minutes
- Reconcile your bank to the last day of the quarter — every transaction accounted for, nothing sitting unallocated.
- Check the GST treatment on anything unusual: overseas subscriptions, bank fees, ASIC fees and insurance stamp duty are the usual traps.
- Confirm any purchase over $1,000 has a valid tax invoice on file. No invoice, no GST credit.
- Split your capital purchases out from your running costs so G10 and G11 are right.
- Run your GST report and compare it against last quarter. A number that has moved by an order of magnitude is usually a coding error, not a great quarter.
- If you have employees, check that gross wages on the BAS agree with what your payroll reported through STP.
- Lodge, then set the payment aside. GST you collected was never your money.
Common questions
Sources
Every rate, threshold and due date in this guide was checked against the pages below on the dates shown. Tax rules change — verify against the ATO before you rely on anything here, and get advice for your own situation.
- Due dates for lodging and paying your BAS — checked 2026-09-27
- When and how to report and pay GST — checked 2026-09-27
- Annual GST reporting — checked 2026-09-27