Published: November 2024, Updated: July 2026
Missing your Business Activity Statement (BAS) deadline is one of the costliest mistakes Australian businesses make. Late lodgement triggers automatic penalties starting at $364 for small businesses (the Commonwealth penalty unit increased on 1 July 2026), plus general interest charge accumulating daily on unpaid amounts at 11.43% per annum. And since 1 July 2025, that interest is no longer tax deductible, so every dollar of ATO interest is now a pure cost.
In 2023, the ATO issued over 180,000 failure to lodge (FTL) penalties for late BAS submissions, collecting approximately $95 million in penalties. Most were preventable with proper calendar management and understanding of actual due dates.
This article explains how BAS due dates work, covers the full 2026-27 deadlines, clarifies the difference between self-lodgement, online lodgement, and registered agent deadlines, and helps you avoid penalties. For a month-by-month FY 2026-27 calendar with a pre-lodgement checklist, see our BAS due dates 2026-27 guide.
A Business Activity Statement reports your GST, PAYG withholding, and other tax obligations to the ATO. If you are registered for GST, you must lodge BAS according to your reporting frequency. Your lodgement frequency depends primarily on your annual GST turnover.
GST-registered businesses: Any business registered for GST must lodge BAS, regardless of turnover. You must register for GST when your annual turnover reaches $75,000 ($150,000 for non-profit organisations). You can voluntarily register below these thresholds.
Businesses with PAYG withholding obligations: If you employ staff and withhold tax from wages, you must report PAYG withholding through BAS even if not registered for GST. Businesses without GST obligations may instead receive an Instalment Activity Statement.
Businesses with other tax obligations: Various other obligations can trigger BAS requirements, including fringe benefits tax instalments, luxury car tax, wine equalisation tax, and fuel tax credits.
Book a call with us to see how we can help you with BAS filing
The ATO assigns your reporting frequency based on GST turnover, though you can sometimes choose more frequent reporting.
Who reports monthly: Businesses with GST turnover of $20 million or more must report monthly. This is mandatory, not optional.
Due date: The 21st day of the month following the reporting month. For example, January 2027 activity is due 21 February 2027 (which falls on a Sunday, so the effective date is Monday 22 February 2027).
Why monthly matters: Large businesses have substantial GST obligations requiring regular reporting and payment. Monthly reporting also means monthly refunds if you are in a GST credit position, improving cash flow.
Real example: A Sydney wholesaler with $28 million annual turnover reports monthly BAS. Their January sales generated $140,000 GST collected from customers and $95,000 GST paid on purchases, resulting in $45,000 owing to the ATO. This is due by 21 February. Missing this deadline triggers immediate penalties plus interest on the $45,000.
Who reports quarterly: Businesses with GST turnover under $20 million can report quarterly. This is the most common frequency for Australian SMEs.
Due dates: The 28th day of the month following each quarter end. Quarters align with July to September (Q1), October to December (Q2), January to March (Q3), and April to June (Q4).
Why quarterly works for SMEs: Quarterly reporting reduces administrative burden compared to monthly and matches typical business planning cycles. Most businesses with $1 million to $20 million turnover use quarterly reporting.
Real example: A Melbourne café with $850,000 annual revenue reports quarterly. Their July to September 2026 quarter generated $23,000 GST collected and $8,500 GST paid, resulting in $14,500 owing. This is due 28 October 2026. They lodge electronically through their accountant, whose agent concession gives them until 25 November 2026.
Who reports annually: Businesses that voluntarily registered for GST despite turnover below $75,000 can choose annual reporting. This is uncommon but available.
Due date: Same date as your income tax return. For individuals and sole traders, this is 31 October following the financial year if lodging yourself, or later if using a registered tax agent. If you are not required to lodge a tax return, the annual GST return is due 28 February following the annual tax period.
Limitation: You can only claim GST credits annually rather than quarterly, impacting cash flow if you make large GST-inclusive purchases.
Q1 2026-27 (July to September 2026): Due 28 October 2026 (Wednesday)
Q2 2026-27 (October to December 2026): Due 28 February 2027, which falls on a Sunday, so the effective due date is Monday 1 March 2027
Q3 2026-27 (January to March 2027): Due 28 April 2027 (Wednesday)
Q4 2026-27 (April to June 2027): Due 28 July 2027 (Wednesday)
Q1 2027-28 (July to September 2027): Due 28 October 2027
Q2 2027-28 (October to December 2027): Due 28 February 2028
Q3 2027-28 (January to March 2028): Due 28 April 2028
Q4 2027-28 (April to June 2028): Due 28 July 2028
July 2026 activity: Due 21 August 2026
August 2026 activity: Due 21 September 2026
September 2026 activity: Due 21 October 2026
October 2026 activity: Due 21 November 2026, which falls on a Saturday, so the effective date is Monday 23 November 2026
November 2026 activity: Due 21 December 2026
December 2026 activity: Due 21 January 2027. A concession to 21 February 2027 (effectively Monday 22 February, as the 21st is a Sunday) applies to business clients with GST turnover of up to $10 million whose registered agent lodges the December BAS electronically under the ATO lodgement program.
January 2027 activity: Due 21 February 2027, which falls on a Sunday, so the effective date is Monday 22 February 2027
February 2027 activity: Due 21 March 2027, which falls on a Sunday, so the effective date is Monday 22 March 2027
March 2027 activity: Due 21 April 2027
April 2027 activity: Due 21 May 2027
May 2027 activity: Due 21 June 2027
June 2027 activity: Due 21 July 2027
If you self-lodge your quarterly BAS online (through Online services for business, myGov, or SBR-enabled software like Xero or MYOB), the ATO says you may be eligible for an extra two weeks to lodge and pay. For 2026-27, that makes the effective online due dates 11 November 2026 (Q1), 12 May 2027 (Q3), and 11 August 2027 (Q4). The concession does not apply to Q2, because the 28 February due date already includes a built-in one-month extension, and it does not apply to monthly or annual lodgers. Our guide on how to lodge BAS online walks through the process.
To check where your next deadline lands, use our BAS lodgement deadline calculator.
One significant advantage of using a registered BAS or tax agent is concessional lodgement dates. Agents receive extended due dates through their participation in the ATO lodgement program. Our guide on what a BAS agent does covers the role in detail.
Registered agents have concessional due dates for client lodgements. These apply automatically when a registered agent lodges electronically on your behalf. You do not need to apply for extensions separately.
Quarterly agent due dates for 2026-27:
Q1 (July to September 2026): Standard due date 28 October 2026, agent due date 25 November 2026
Q2 (October to December 2026): Standard and agent due date both 28 February 2027 (effectively 1 March 2027 after the weekend shift). There is no additional agent extension for Q2 because the due date already includes a one-month extension.
Q3 (January to March 2027): Standard due date 28 April 2027, agent due date 26 May 2027
Q4 (April to June 2027): Standard due date 28 July 2027, agent due date 25 August 2027
Critical requirements: These extensions only apply if you formally engage a registered agent, they lodge electronically, and your previous activity statement was lodged electronically. If it's your first activity statement or your previous one went in on paper, an earlier due date may apply. Simply planning to use an agent without formal engagement does not grant extensions.
Real example: A Brisbane retailer engages their accountant as their registered BAS agent in August 2026. Their Q1 BAS (July to September 2026) has a standard due date of 28 October 2026, but their agent's concessional due date is 25 November 2026. This extra four weeks allows better month-end processing and reconciliation before lodgement.
Monthly activity statements do not receive agent extensions, with one exception: the December monthly BAS. Eligible business clients (GST turnover up to $10 million, reporting GST monthly, lodged electronically by their agent) get until 21 February instead of 21 January. Businesses registered for deferred GST are not eligible.
Agent concessions are lost if your previous activity statement was lodged on paper, your agent withdraws from representing you, or you have outstanding compliance issues with the ATO. If you miss your agent's extended deadline, you face penalties as though you missed a deadline in the ordinary way. The ATO does not provide additional leniency because you had extra time.
ATO online services: Log into Online services for business (or myGov for sole traders), and complete your BAS online. The system calculates amounts automatically based on your entries. Payment can be made electronically immediately, and online lodgement is what qualifies you for the two-week quarterly concession.
SBR-enabled software: Xero, MYOB, and QuickBooks all support lodging directly from your accounting file, pre-filled from your coded transactions.
Paper lodgement: Paper BAS forms can be mailed to the ATO, though this method is increasingly discouraged. Processing takes longer, you miss electronic lodgement confirmations, and you forgo the online concession.
Important timing consideration: If you lodge electronically on the due date, you have until 11:59 PM that day. If you lodge by paper, Australia Post delivery times apply, so you should mail several days before the due date to ensure timely receipt.
Most Australian SMEs engage registered BAS agents (typically accountants or bookkeepers) to prepare and lodge BAS. This provides professional review reducing errors, concessional due dates providing extra time, integration with year-end tax planning, and peace of mind that obligations are met correctly.
Agent lodgement process: Your bookkeeper or accountant prepares BAS from your accounting software, reviews for accuracy and unusual items, obtains your approval, lodges electronically through their registered agent portal, and provides you with lodgement confirmation and payment instructions.
Cost considerations: BAS agent fees typically range from $150 to $500 per BAS depending on business complexity and transaction volume. Quarterly lodgement for a business with $2 million turnover might cost $250 to $350 per quarter. This investment often saves more through error prevention and the extra four weeks of breathing room each quarter.
When a BAS due date falls on a weekend or public holiday, the due date automatically extends to the next business day. This applies to both lodgement and payment.
The 2026-27 year has a live example: the Q2 due date of 28 February 2027 falls on a Sunday, so quarterly lodgers have until Monday 1 March 2027. On the monthly cycle, October 2026 activity (due 21 November, a Saturday) rolls to Monday 23 November 2026, and both the January and February 2027 statements roll from Sunday the 21st to the following Monday.
Understanding penalty structures helps you appreciate the importance of timely lodgement and payment.
The ATO can issue FTL penalties when you lodge late. The penalty is calculated in 28-day blocks: one base penalty amount for each 28 days (or part thereof) the statement is overdue, capped at five blocks. The base amount depends on your business size, and the Commonwealth penalty unit increased to $364 on 1 July 2026 (up from $330).
Small businesses (turnover under $1 million): One penalty unit per 28-day block, currently $364, up to a maximum of $1,820 per late statement.
Medium businesses (turnover $1 million to $20 million): Two penalty units per block, currently $728, up to a maximum of $3,640.
Large businesses (turnover over $20 million): Five penalty units per block, currently $1,820, up to a maximum of $9,100.
These penalties apply per late lodgement, and they apply even if you owe no GST or are due a refund. A small business that lodges four quarterly BAS a few days late each time faces at least $1,456 in penalties ($364 x 4) despite potentially owing nothing.
When you lodge late and owe money to the ATO, GIC applies daily on the unpaid amount from the original due date until payment. The GIC rate changes quarterly based on the 90-day bank bill rate plus 7%. For the July to September 2026 quarter, the GIC rate is 11.43% per annum (approximately 0.0313% per day, compounding daily).
The deductibility change matters: GIC (and shortfall interest charge) incurred on or after 1 July 2025 is no longer tax deductible, regardless of when the underlying debt arose. ATO interest used to be softened by a tax deduction. It is now a pure cost, and at over 11% it is more expensive than most commercial finance.
Calculation example: A Brisbane manufacturer owes $12,000 GST for their January to March 2027 quarter, due 28 April 2027. They lodge and pay on 28 June 2027, 61 days late.
FTL penalty: $728 (medium business, within the first 28-day blocks)
GIC: $12,000 x 61 days x 0.0313% daily = approximately $230 (slightly more once daily compounding is applied)
Total penalties and interest: roughly $958 on top of the $12,000 owed, none of it deductible.
For repeated non-compliance, the ATO can apply further administrative penalties and escalate to firmer debt recovery. For company directors, unpaid PAYG withholding, GST, and superannuation can become a personal liability through Director Penalty Notices. This applies to company directors, not sole traders, and is one of the strongest reasons to lodge and pay on time even when cash is tight.
Set calendar reminders: Electronic calendar entries 7 days before BAS due dates give you buffer time. If using a registered agent, set reminders 14 days before agent due dates to allow time for preparation and review.
Use accounting software prompts: Xero, MYOB, and QuickBooks all include BAS preparation and lodgement prompts. Configure these to alert you well before deadlines.
Engage a registered agent: Agent concessions provide extra time, reducing the risk of missing deadlines. Professional preparation also minimises errors.
Lodge even if you cannot pay: If cash flow prevents immediate payment, lodge your BAS on time and contact the ATO to arrange a payment plan. Lodging on time avoids FTL penalties. GIC still accrues on the unpaid amount, and now that it's non-deductible, clearing ATO debt quickly is worth more than it used to be.
Maintain good ATO standing: Businesses with clean compliance histories may receive penalty remission if they lodge late once due to genuine oversight. Serial late lodgers receive no leniency.
Some businesses receive Instalment Activity Statements rather than BAS. IAS applies to businesses with PAYG instalments or PAYG withholding but no GST reporting obligation. Quarterly IAS follows a similar cycle to quarterly BAS. See our full guide on IAS vs BAS for the differences.
Businesses with GST turnover under $10 million use Simpler BAS, reporting only total sales, GST on sales, and GST on purchases. This reduces the labels you complete but does not change your due dates.
Your first BAS covers the period from your GST registration date to the end of the relevant reporting period. If you register for GST on 15 August 2026 with quarterly reporting, your first BAS covers 15 August to 30 September 2026 (partial quarter), due 28 October 2026.
The ATO confirms your GST registration date and first BAS due date. Mark this carefully as missing your first BAS creates immediate compliance problems, and agent concessions may not apply to a first statement.
When you close your business and cancel GST registration, you must lodge a final BAS covering the period up to your cancellation date. Ensure all income and expenses up to the closing date are captured, all GST collected is remitted, and you claim all GST credits on final expenses. Many businesses miss claiming GST on closing costs like final stock clearance or lease termination.
If you realise you have missed a BAS deadline, lodge immediately and include a voluntary disclosure explaining the delay. The ATO may reduce penalties if you proactively disclose and correct the mistake before they contact you.
Lodging your BAS creates the obligation, but payment must occur separately (unless using software that integrates lodgement and payment).
Electronic payment options:
BPAY using your Payment Reference Number (PRN)
Direct bank transfer to the ATO using your PRN
Credit or debit card through the ATO payment portal (a card payment fee applies depending on card type)
Payment plans for amounts you cannot pay immediately
Payment timing: Payments must reach the ATO by the due date. Bank transfers can take 1 to 2 business days to process, so best practice is to pay 2 to 3 days before the deadline. GIC starts accruing the day after the due date on any unpaid balance.
If you cannot pay your BAS by the due date due to cash flow difficulties, contact the ATO immediately to arrange a payment plan. The ATO is generally accommodating if you communicate proactively.
Payment plan considerations:
Lodge your BAS on time even if you cannot pay (avoids FTL penalties)
Contact the ATO before the payment due date if possible
Propose a realistic payment schedule you can actually meet
GIC continues to accrue at the full rate on the outstanding balance for the life of the plan, and it is no longer deductible, so shorter plans cost meaningfully less than longer ones
Payment plans protect you from debt recovery action while you pay down the amount, and the ATO can remit some interest in limited circumstances, but remission is discretionary, not automatic
Example payment plan: A Sydney retailer owes $22,000 GST for the October to December 2026 quarter but lacks cash flow to pay in full by 1 March 2027. They lodge on time and immediately contact the ATO proposing six monthly payments of $3,667. The ATO approves the plan. GIC accrues on the reducing balance throughout, but the business avoids FTL penalties and recovery action.
Superannuation guarantee used to run on the same quarterly rhythm as BAS, but that changed on 1 July 2026. Under Payday Super, employers must now pay super with every pay run, and contributions must reach each employee's fund within 7 business days of payday. The final quarterly super payment (for the June 2026 quarter) was due 28 July 2026.
Super is reported through Single Touch Payroll, not through your BAS. What your BAS does capture is PAYG withholding from employee wages: your quarterly BAS shows total wages (W1) and tax withheld (W2) for the period, which should reconcile to your STP reporting.
When is BAS due for 2026-27?
Quarterly BAS is due 28 October 2026 (Q1), 1 March 2027 (Q2, shifted from Sunday 28 February), 28 April 2027 (Q3), and 28 July 2027 (Q4) for standard self-lodgers. Online quarterly lodgers may be eligible for an extra two weeks on Q1, Q3, and Q4. Monthly BAS is due the 21st of the following month. Registered agents lodging electronically get until 25 November 2026, 26 May 2027, and 25 August 2027 for quarters 1, 3, and 4.
What happens if I lodge my BAS late?
The ATO can issue failure to lodge penalties of one penalty unit ($364 from 1 July 2026) per 28 days overdue for small businesses, capped at five units ($1,820), with medium and large businesses paying two and five times those amounts. If you owe money, general interest charge accrues daily from the original due date at 11.43% per annum (July to September 2026 rate), and it is not tax deductible.
How long does a BAS refund take after lodgement?
The ATO typically processes BAS refunds within 12 business days for electronic lodgements. Delays can occur if your business has outstanding ATO debt (the ATO may offset refunds against other amounts owing), a history of late lodgements or compliance issues, or unusual transactions requiring review. Paper lodgements take significantly longer.
Do I have to lodge BAS if my turnover is under $75,000?
You only lodge BAS if you are registered for GST. If your turnover is under $75,000, GST registration is voluntary, not mandatory. However, if you voluntarily register for GST (for example, to claim GST credits on business purchases), you must lodge BAS according to your reporting frequency regardless of actual turnover.
Can I get extra time without using an agent?
Yes, for quarterly BAS: lodging online rather than on paper may qualify you for an extra two weeks on quarters 1, 3, and 4. Beyond that, individual extensions are rare and generally only granted in exceptional circumstances like natural disasters or serious illness. The four-week concessions belong to registered agents through the ATO lodgement program.
Can I change from quarterly to monthly BAS reporting?
Businesses under $20 million turnover can voluntarily elect monthly reporting by contacting the ATO. This might suit businesses that want faster GST refunds or prefer monthly cash flow management. You cannot change from monthly to quarterly if your turnover exceeds $20 million. Changes typically take effect from the start of the next quarter or year depending on when you request them.
What if the due date falls on a weekend?
When a BAS due date falls on a weekend or public holiday, the deadline automatically extends to the next business day. The 2026-27 Q2 deadline is the live example: 28 February 2027 is a Sunday, so lodgement and payment are due Monday 1 March 2027.
Do I need to lodge BAS separately for each business I own?
Each separate business entity (each ABN) requires its own BAS. If you operate multiple companies, each company lodges separately. If you run multiple businesses through one ABN (for example, two separate activities under your sole trader ABN), you report all activity on one BAS.
How do payment plans affect BAS penalties?
Arranging an ATO payment plan does not eliminate penalties that have already been applied, but can prevent recovery action. GIC continues to accrue at the full rate on unpaid amounts for the life of the plan, and since 1 July 2025 that interest is not deductible. The key is lodging on time to avoid FTL penalties, then arranging payment terms for amounts you cannot pay, and clearing the balance as quickly as you can.
What is the penalty if I forget to charge GST on sales?
You still owe the GST to the ATO even if you forgot to charge customers. If you invoiced $10,000 for services but forgot to add GST, you owe the ATO $909 ($10,000 divided by 11) from your own funds. The ATO does not waive GST because you made a charging error. This is why GST-registered businesses must ensure their invoicing systems automatically apply GST.
Do I report PAYG withholding separately or through BAS?
PAYG withholding from employee wages is reported through your BAS using the W1 and W2 labels. The amounts reported should match your Single Touch Payroll (STP) reporting. Pay-as-you-go instalments for your own business income tax may appear on your BAS or on a separate Instalment Activity Statement depending on your circumstances.
Scale Suite is a Sydney-based provider of outsourced finance teams and fractional CFO services for Australian SMEs. We deliver weekly bookkeeping, payroll, BAS/IAS lodgement, cashflow reporting, management accounts, and strategic fractional CFO oversight - all as a fully embedded team that works inside your business.
CA-qualified, Xero Certified, and registered BAS Agents, we replace fragmented bookkeepers and once-a-year accountants with one responsive finance function at a fraction of the cost of full-time hires. We serve growing businesses across Sydney, Melbourne, Brisbane, and Perth, with packages starting from $1,500 per month and no lock-in contracts.
Learn more about our embedded finance model at scalesuite.com.au/services/finance
We review and check this guide periodically. At the time of writing (July 2026), all information was current. Due dates, penalty amounts, and interest rates are as published by the ATO for the 2026-27 financial year and are subject to change. Scale Suite is a registered BAS Agent, not a licensed tax advisor or financial advisor. This content is general information only and does not constitute professional tax, financial, or legal advice. Always confirm current dates and rates with the ATO or a registered professional.
Scale Suite is a Sydney-based provider of outsourced finance and HR services for Australian SMEs. We deliver bookkeeping, financial reporting, payroll processing, fractional CFO support, recruitment, employee onboarding, people and culture support, and fractional HR oversight, all as a fully embedded team that works inside your business.
Employment Hero Gold Partner, CA-qualified, and Xero Certified, we replace fragmented finance and HR processes with one responsive, senior-level function at a fraction of the cost of full-time hires. We serve growing businesses across Sydney, Melbourne, Brisbane, and Perth, with packages starting from $1,500 per month and no lock-in contracts.
30 minutes with our team.
We'll review your current finance setup, compare the full cost of an internal hire against our embedded team, and show you exactly what your finance function should cost at your stage of growth.
You'll leave with a clear view of what's working, what's missing, and where you'd save.
No lock-in contracts. 30-day money-back guarantee.
Prefer to book directly? Grab a time here.
