BAS is stressful for one reason: most businesses do three months of bookkeeping in the week it is due. The statement itself is not difficult. Reconstructing a quarter from a shoebox under deadline is.
This is how the quarter works, when it is actually due, and the monthly rhythm that turns lodgement into a non-event.
When you have to be in the system at all
You must register for GST once your GST turnover reaches, or is projected to reach, $75,000 in a rolling or projected twelve month period. For not-for-profit organisations the threshold is $150,000.
The word projected matters and is where new businesses get caught. It is not only about what you have already turned over. If you sign a contract in August that will clearly take you past $75,000 within twelve months, the obligation is triggered by that expectation, not by waiting until the money has landed.
Once registered, you charge GST on your sales, claim it on your purchases, and report the difference on a business activity statement.
The dates, so they are in one place
Most small businesses lodge quarterly. The quarters and their standard due dates are:
| Quarter | Period covered | Standard due date |
|---|---|---|
| Quarter 1 | July, August, September | 28 October |
| Quarter 2 | October, November, December | 28 February |
| Quarter 3 | January, February, March | 28 April |
| Quarter 4 | April, May, June | 28 July |
Quarter 2 gets the longest run because it covers the Christmas period. If you lodge through a registered tax or BAS agent, different dates may apply, which is worth confirming rather than assuming.
Note what these dates are not. They are not the date to start. A quarter due on 28 October ends on 30 September, so if you begin on 20 October you are reconstructing three months from memory and a folder of receipts with four working days left.
Why the panic is a bookkeeping problem, not a BAS problem
Ask someone who finds BAS stressful what specifically is hard, and the answer is almost never the form. It is that they do not know which transactions are business, what that unlabelled transfer was, whether the tools purchase had GST on it, or where the receipt went.
That is not a lodgement problem. It is three months of uncoded bank feed arriving all at once, and the statement is simply the moment it becomes unavoidable.
A quarter reconstructed under deadline is a quarter with errors in it. Work done at speed on incomplete information produces guesses coded as facts, and those guesses sit in your ledger until someone reconciles the control accounts months later.
The monthly rhythm that removes it
The businesses that find BAS boring all do the same thing. They close each month rather than each quarter. By the time the statement is due, two of the three months are already finished and checked.
A workable monthly close is four things:
- Reconcile every bank and card account to the statement. Not roughly, to the cent. An unreconciled account means the figures underneath it are unverified.
- Clear the suspense account to zero. Anything you could not identify goes there during the month and comes back out before the month closes. This is the single habit that prevents two years of unexplained transactions accumulating.
- Check the GST control account against what you have actually reported. A drift here is the early warning that a recurring item is coded wrong, and catching it in month one saves correcting four quarters later.
- Lock the period. Once a month is closed and checked, prevent anyone posting into it. Without this, last quarter’s figures quietly change after you have lodged on them.
Do that and the quarter end is an hour of review, not a week of archaeology.
Behind on more than one quarter?
Catch-up work is scoped as a fixed price project so you know the cost before it starts, not after.
The five things that go wrong most
- GST claimed on something that never carried it. Bank fees, most residential rent, some insurance components and many government charges. Claiming GST that was never paid is a real error with a real correction.
- A recurring item coded wrong at setup. One bad rule repeated every month for two years is a large adjustment discovered all at once.
- Private expenses through the business account. Not a problem in itself, provided they are identified and treated properly rather than quietly claimed.
- Vehicle and entertainment treated as ordinary purchases. Both have their own rules and both are commonly claimed in full when they should not be.
- The statement lodged from a file that does not reconcile. If the bank account does not agree to the statement, the GST figure is a guess with decimal places.
Who is allowed to lodge it
This is worth being clear about, because the distinction is not obvious from the outside.
You can lodge your own BAS. Beyond that, only a registered BAS agent or registered tax agent can lodge on your behalf or give you advice about your BAS obligations. Registration is administered by the Tax Practitioners Board and you can check any practitioner on the public register.
We are not a registered BAS agent and we do not lodge. What we do is get the file into a state where lodgement is straightforward: every account reconciled, GST coded line by line, the quarter checked, and a working paper your registered agent can lodge from without coming back with questions. Plenty of firms blur this line. We would rather tell you where it sits.
If you do not currently have a registered agent, that is worth sorting out before the next quarter rather than during it.
Where to start if you are already behind
Do not begin with the oldest quarter. Begin with the current one, so you stop the problem growing, then work backwards. A business that is four quarters behind and lodging late every quarter is in a worse position than one that is four quarters behind but current from today.
If the gap is large, scope it as a project with a fixed price rather than paying hourly into an open ended clean-up. Our BAS-ready bookkeeping covers the ongoing rhythm, and catch-up bookkeeping covers the backlog.
Thresholds and due dates in this article apply for the 2026-27 financial year and are drawn from the Australian Taxation Office. Confirm your own circumstances before relying on this for a specific lodgement.
