In Australia, Business Activity Statements (BAS) are a critical part of staying tax-compliant for GST-registered businesses. Whether you’re a sole trader or a growing company, understanding your BAS obligations is essential.
In this guide, we break down what BAS is, who needs to lodge it, how often, and what to include — plus the most common BAS mistakes small businesses make.
1. What is a BAS?
A BAS (Business Activity Statement) is a tax reporting form that businesses submit to the Australian Taxation Office (ATO). It is used to report and pay:
- Goods and Services Tax (GST)
- Pay As You Go (PAYG) withholding
- PAYG instalments
- Fringe Benefits Tax (FBT) instalments
- Other taxes, depending on your registration
You only need to lodge a BAS if your business is registered for GST or other obligations like PAYG.
2. Who Needs to Lodge BAS?
You must lodge a BAS if:
✅ Your business is registered for GST (annual turnover over $75,000, or $150,000 for non-profits)
✅ You have employees and need to report PAYG withholding
✅ You’ve voluntarily registered for GST
Even if you have no sales in a given period, you’re still required to lodge a nil BAS.
3. How Often Do You Need to Lodge BAS?
BAS lodgement frequency depends on your GST turnover:
| Annual GST Turnover | Lodgement Frequency | Due Date |
| $20 million or more | Monthly | 21st of next month |
| Under $20 million | Quarterly (default) | 28th of next quarter |
| <$75,000 (voluntary GST registration) | Annually (if approved) | As advised by ATO |
Tip: Most small businesses lodge quarterly — it balances reporting and admin effort.
4. What to Include in Your BAS
Your BAS includes several sections depending on your registrations:
✅ GST Section:
- GST collected on sales
- GST paid on purchases (input tax credits)
- Adjustments (bad debts, over/under claims)
✅ PAYG Withholding:
- Tax withheld from employee wages
✅ PAYG Instalments:
- Income tax instalments (based on ATO estimates or your own)
✅ Other:
- FBT instalments
- Wine equalisation tax or luxury car tax (if applicable)
Reminder: Even if you’re only registered for GST, the other fields must be marked as Not Applicable or left blank appropriately.
5. How to Lodge Your BAS
There are several ways to lodge BAS with the ATO:
- Through a registered BAS or tax agent (like Ozobooks)
- Via the ATO Business Portal
- Using your accounting software (e.g., Xero, MYOB, QuickBooks)
Tip: Lodging through your software is fast and helps minimise errors due to auto-calculation and integrated bank feeds.
6. Due Dates & Penalties
Quarterly BAS due dates:
- Q1 (Jul–Sep): 28 October
- Q2 (Oct–Dec): 28 February
- Q3 (Jan–Mar): 28 April
- Q4 (Apr–Jun): 28 July
Late Lodgement Penalties:
- ATO imposes a Failure To Lodge (FTL) penalty → starts at $313 (1 penalty unit) for every 28 days late, up to 5 units.
- Interest may apply on overdue amounts (General Interest Charge – GIC).
7. Common BAS Mistakes to Avoid
❌ Incorrectly claiming GST credits
Claiming GST on purchases that are not GST-taxable (e.g., insurance premiums, certain government fees).
❌ Failing to reconcile sales data
BAS lodged based on estimates rather than actual reports → can trigger audits.
❌ Missing adjustments
Omitting GST adjustments for bad debts, cancelled sales, or prior period corrections.
❌ Late lodgements
Even consistent delays can raise red flags with ATO.
8. How to Prepare for Lodgement
Before lodging:
✅ Reconcile all bank transactions
✅ Verify GST coding on all purchases and sales
✅ Cross-check totals in your accounting software
✅ Ensure payroll reports are aligned with PAYG
✅ Review GST adjustments and rounding errors
✅ Save supporting documents for audit trail
Pro tip: Schedule monthly bookkeeping so quarterly BAS isn’t a last-minute scramble.
9. Benefits of Using a BAS Agent
Partnering with a registered BAS agent offers:
- Lodgement deadline extensions
- Error detection & corrections
- Guidance on GST disputes or ATO notices
- Accurate reporting & peace of mind
📌 Related: Bookkeeping & Reconciliation | BAS & GST Reporting
Final Thoughts: BAS Done Right with Ozobooks
Timely, accurate BAS lodgement helps your business stay compliant and avoids unnecessary penalties. Whether you’re managing quarterly reports or reconciling GST with international sales, the right support makes all the difference.
👉 Need help with BAS lodgement in Australia?
📞 Contact Ozobooks — your trusted BAS & bookkeeping partner.
