Set aside GST in a separate bank account: a simple routine for your quarterly BAS

GST you collect in October isn't due until the end of February

The BAS year, 1 July 2026 to 31 July 2027, to scale

Quarter 1, July to Septemberdue 28 October
Quarter 2, October to Decemberdue 28 February (a Sunday: the next business day, Monday 1 March)
Quarter 3, January to Marchdue 28 April
Quarter 4, April to Junedue 28 July

The quarter The wait until the BAS is due. Christmas Day is Friday 25 December 2026 and New Year's Day is Friday 1 January 2027.

Quarterly BAS due dates, from the ATO.

Sources: ATO, due dates for lodging and paying your BAS; Fair Work Ombudsman, public holidays

If you lodge quarterly, the GST you collect on 1 October stays in your business for 150 days before it's due. That's our count, from 1 October to the ATO's Quarter 2 (Oct–Dec) due date of 28 February.

We ran the same count for the other three quarters on the ATO's list, with due dates of 28 October, 28 April and 28 July. Each comes to between 117 and 119 days. So the October to December quarter holds your GST about a month longer than any other. That extra month runs straight through Christmas, New Year and the January quiet patch.

The longer the money sits beside your takings, the easier it is to spend. The ATO puts it plainly: if GST you collect gets mixed into cash flow, it's easy to spend it and be short at BAS time. Its first tip is the fix: separate the GST.

One date check before you plan around it: 28 February 2027 falls on a Sunday (our calendar check). Look at the due date printed on your own BAS, and aim to have the money ready by Friday 26 February.

Why the GST in your bank account isn't yours to spend

The path a GST dollar takes

Customer pays your invoice, GST included Lands in your everyday account

Your money

Separate GST account (don't spend)BAS: GST collected minus GST credits Collected more than you claim: pay the differenceCredits higher: you may get a refund

GST share stays in the everyday accountWages, stock, Christmas costsShort at BAS time

The solid path keeps the GST apart until the BAS. The faded path is what happens when it stays in the everyday account. Shares are schematic.

Source: ATO, make BAS time easier following our 3 tips

When a customer pays your invoice, the GST arrives in the same account as everything else. Your balance looks healthier than it is. Part of every payment is money you're holding for the ATO until the BAS is due.

That's why a quarter with a long gap is risky. Wages, stock, rent and Christmas costs all draw on the same balance, and nothing marks which dollars are already spoken for. A separate account does that marking for you. It doesn't change what you owe. It changes whether the money is still there when you need it.

How to set aside GST in a separate bank account

The weekly set-aside routine

Open one or more separate accounts: GST, PAYG withholding or instalments, super, end-of-year income taxATO small business course
Transfer a portion of income across each weekATO small business course
Set aside PAYG withholding and super as wellATO newsroom, April 2025
Keep the GST separate from day-to-day cash flow so you're ready to pass it on at BAS timeATO newsroom, 3 tips
Schedule time in your calendar to prepare the BASATO newsroom, April 2025
Keep an eye on upcoming expensesATO newsroom, April 2025
Optional: make early payments to offset a future BASATO due dates page

Tick each line as it goes into your week.

The ATO's advice is to keep GST apart from day-to-day cash flow, for example in a separate bank account, so you don't spend it unintentionally. Its small business course goes further and suggests one or more separate bank accounts for GST, PAYG withholding or instalments, super and end-of-year income tax. Its worked example is a sole trader who moves a portion of income across every week.

An earlier ATO article adds three habits: set aside PAYG withholding and super as well, schedule time in your calendar to prepare the BAS, and keep an eye on upcoming expenses.

At ARC Business Development, this is the routine we'd suggest building from that advice:

Pick one day a week. Friday afternoon is one option. The habit matters more than the day.
Move the GST on what came in that week. If you use the non-cash basis, work from invoices issued rather than payments received, because that's what lands in your BAS (more on that below).
Move PAYG withholding and super at the same time. One transfer session, three buckets.
Treat the GST account as the ATO's money. No borrowing from it for a slow week.
Consider paying ahead. The ATO lets you make early payments to offset a future BAS liability, which moves the money out of your everyday account and towards that BAS.

How much GST do I owe? GST collected minus GST credits

Net GST

GST collected on taxable sales−GST credits on business purchases=Net GST

Collected more than you claim: you pay the difference
Credits higher: you may get a refund

Net GST is what the BAS comes down to.

Source: ATO, make BAS time easier following our 3 tips

The ATO's second tip is to review your cash flow: check how much GST you collect and how much you can claim. Net GST is GST collected on taxable sales minus GST credits on business purchases. If you collect more than you claim, you pay the difference. If your credits are higher, you may get a refund.

Can I claim this GST credit?
Rule	Source
Tax invoice needed to claim a GST credit, except purchases of $82.50 or less (checked October 2026)	ATO, choosing an accounting method
You have 4 years to claim credits	ATO, choosing an accounting method
Mixed-use purchases: claim only the business portion	ATO, BAS and GST tips
GST-free items: no credit	ATO, BAS and GST tips
Purchases with no GST in them, such as bank fees: no credit	ATO, BAS and GST tips
Keep tax invoices and GST records for 5 years	ATO, BAS and GST tips

Six rules for claiming a GST credit.

Credits only reduce your bill if you can back them up. You need a tax invoice to claim a GST credit, except for purchases of $82.50 or less (checked October 2026), and you have 4 years to claim. The ATO's BAS and GST tips say to keep tax invoices and GST records for 5 years, and to claim only the business portion of mixed-use purchases. GST-free items and purchases with no GST in them, such as bank fees, carry no credit.

If your weekly transfer uses a rough GST share of sales, it may set aside a little more than your net bill, since credits come off at the end. That's the safe direction to be wrong in. For the exact figure on your own BAS, check with a registered tax or BAS agent.

Cash or non-cash basis: which BAS a sale lands in

Which BAS does a sale land in?
What	Cash basis	Non-cash basis
GST on a sale	Period you receive payment	Period you issue the tax invoice or receive payment, whichever comes first
GST credits	Period you pay	Period you receive the supplier's tax invoice or make any payment, whichever comes first
Invoice issued in December, paid in January	January to March BAS	October to December BAS

Businesses with aggregated turnover under $10 million can choose either method.

Cash and non-cash side by side.

Source: ATO, choosing an accounting method

Your GST accounting method decides which BAS a sale or purchase lands in. Businesses with aggregated turnover under $10 million can choose cash or non-cash.

On the cash basis, GST on a sale goes in the BAS for the period you receive payment, and credits go in the period you pay. The ATO says this aligns the money flowing through the business with your BAS liabilities.

On the non-cash basis, you account for GST on a sale in the period you issue a tax invoice or receive payment, whichever comes first. A December invoice that the customer pays in January still belongs in your October to December BAS. You owe that GST in February even if the customer is slow. If that's you, set aside GST when you invoice, not when you're paid.

BAS due dates, and why lodging online doesn't move the February one

BAS due dates
Period	Due
Quarter 1, July to September	28 October
Quarter 2, October to December	28 February (already includes a one-month extension; the later online-lodgment date does not apply). In 2027 that is a Sunday, so the next business day, Monday 1 March
Quarter 3, January to March	28 April
Quarter 4, April to June	28 July
Monthly reporters	21st of the following month

Quarterly reporting applies if GST turnover is under $20 million and the ATO hasn't directed you to report monthly; under $20 million you can choose monthly.

Quarterly and monthly BAS due dates.

Source: ATO, due dates for lodging and paying your BAS

The ATO's quarterly due dates are 28 October, 28 February, 28 April and 28 July. You report quarterly if your GST turnover is under $20 million and the ATO hasn't directed you to report monthly. Monthly BAS is due on the 21st of the following month, and you can choose monthly reporting under $20 million. The ATO lists smaller, more manageable payments among its benefits.

Lodging online doesn't buy two extra weeks on the February BAS: the ATO says the later due date does not apply to Quarter 2, because 28 February already includes a one-month extension.

Two more points from the ATO's BAS and GST tips: a nil BAS still has to be lodged by the due date, and you can fix most GST mistakes in your current BAS.

Christmas and January: the stretch your GST has to get through

The quarter that holds GST longest is also the one with the thinnest trading weeks. Christmas Day falls on Friday 25 December 2026 and New Year's Day on Friday 1 January 2027 in every state and territory. Plan for quieter trading weeks around them.

December can also bring extra costs: bonuses, holiday pay and super due on a tighter timetable than last year. We covered those dates in Payday Super: planning your cash flow for every pay run and the Christmas period.

The GST account is what stops January's quiet weeks from eating the February bill. Put the BAS payment into your cash flow forecast as a fixed line in late February, at the amount your GST account says, not the amount you hope to have.

If you can't pay your BAS in full on time

General interest charge (GIC), reviewed quarterly.
Quarter	Annual rate
July to September 2026	11.43% a year
October to December 2026	11.51% a year, daily rate 0.03153425%

Checked October 2026. The rate is reviewed each quarter.

Source: ATO, general interest charge rates

Ring the ATO or your registered tax professional before the due date, not after. If you owe $200,000 or less, you may be able to set up a payment plan online (checked October 2026). Payment plans need an up-front payment, and the general interest charge keeps accruing while you pay.

That charge can apply when an amount stays unpaid after its due date. For October to December 2026 the annual rate is 11.51%, a daily rate of 0.03153425% (checked October 2026). The rate is reviewed quarterly, so the one that applies after the February due date may differ.

Our estimate, at the October to December 2026 rate: each $10,000 left unpaid costs about $3.15 a day ($10,000 × 0.03153425%), or roughly $95 over 30 days. Small per day, but it's money spent on nothing, and it's the cost the ATO's third tip, pass it on by lodging and paying in full and on time, is there to avoid.

GST and BAS figures in one place

GST and BAS in five lines

Quarter 2 (October to December) BAS
due 28 February (in 2027 a Sunday, so Monday 1 March); the later online-lodgment date does not apply
Source: ATO due dates
Monthly BAS
due the 21st of the following month
Source: ATO due dates
GIC for October to December 2026
11.51% a year (checked October 2026), reviewed quarterly
Source: ATO GIC rates
GST credits
tax invoice needed, except purchases of $82.50 or less
Source: ATO accounting method
If you can't pay in full
online payment plan may be possible if you owe $200,000 or less; up-front payment needed, GIC keeps accruing
Source: ATO due dates

Five figures, each with its ATO page.

The figures above on one card, each from the ATO page it came from. The GIC rate is the one to refresh each quarter.

Your next step with ARC Business Development

Start with one action this week: open the separate account and make the first transfer for October's sales. The second transfer is easier than the first, and by February the habit has done the work.

If you'd like help building that routine into how your business runs its numbers, book a 20-minute conversation with Andrew at ARC Business Development. For anything specific to your own tax position, talk to your registered tax or BAS agent.