Quarterly BAS is due on the 28th of the month after each quarter ends: 28 October, 28 February, 28 April and 28 July. Monthly BAS is due the 21st of the following month. The December quarter gets an extra month built in (28 February, not 28 January), and lodging through a registered agent generally buys additional time on the other three quarters.
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The quarterly calendar.
| Quarter | Period | Standard due date |
|---|---|---|
| Q1 | July – September | 28 October |
| Q2 | October – December | 28 February |
| Q3 | January – March | 28 April |
| Q4 | April – June | 28 July |
Two quirks worth knowing: the December quarter already includes a holiday extension (that's why it's 28 February), and when any due date lands on a weekend or public holiday, you have until the next business day.
Monthly and annual cycles.
- Monthly BAS is due the 21st of the following month: July's BAS by 21 August, and so on. Monthly reporters don't get the December extension.
- Annual GST returns (only available under the $75,000 threshold) are due with your income tax return, or 28 February if you don't have to lodge one.
Agents get extra time.
Lodging through a registered BAS or tax agent generally adds several weeks to the standard quarterly deadlines under the ATO's agent lodgement program (the December quarter is the exception. Its extension is already built in). If deadlines are the part of GST you hate, an agent is the cheapest calendar you'll ever buy.
If you're late.
Two separate things happen: a failure-to-lodge penalty on the form, which grows the longer it's outstanding, and general interest on any unpaid amount. They're independent, so if cash is short, lodge on time anyway and arrange a payment plan for the balance. A lodged-but-unpaid BAS is a much smaller problem than a missing one.
How to never miss one.
- Put all four dates in your calendar now. They don't move.
- Reconcile monthly, not quarterly. The BAS becomes a read-out (what's on the form).
- Set your reporting cycle deliberately at registration, quarterly suits most; the accounting method matters too.
Quick answers.
What if the BAS due date falls on a weekend?
You can lodge and pay on the next business day without penalty: the deadline rolls forward automatically.
Do I get more time lodging through an agent?
Generally yes, registered agents' clients get extended quarterly deadlines under the ATO's lodgement program, except the December quarter, whose extension (28 February) is already built into the standard date.
What if I can't pay my BAS by the due date?
Lodge it on time anyway. Lodgement and payment are penalised separately, and the ATO offers payment plans: interest accrues on the balance, but you avoid the failure-to-lodge penalty entirely.
Which due dates apply to me: monthly or quarterly?
Whichever reporting cycle is on your GST registration. Quarterly is the default for most small businesses; monthly is compulsory above $20 million turnover and optional below it; annual is only available under $75,000.
Related guides: BAS calculator · What is a BAS? · Fixing BAS mistakes · Cash vs accrual GST · GST instalments · Do I need to register for GST?
Start with the right cycle. We set it at registration.
Lodged by Registered BAS Agent 25972850 · tax deductible · free help on 1800 546 526.