Introduction
Running a business in Australia comes with several compliance responsibilities, and BAS & GST accounting is one of the most important. Whether you are a small business owner, startup founder, or an established company, accurate handling of Business Activity Statements (BAS) and Goods and Services Tax (GST) is essential to avoid penalties, maintain cash flow, and stay compliant with Australian tax laws.

This detailed guide explains everything Australian companies need to know about BAS and GST accounting—from registration and reporting to benefits of professional accounting support.
What is BAS Accounting in Australia?
BAS (Business Activity Statement) is a form submitted to the Australian Taxation Office (ATO) that reports business tax obligations. Through BAS, companies declare and pay various taxes, including:
- Goods and Services Tax (GST)
- Pay As You Go (PAYG) withholding
- PAYG income tax instalments
- Fringe Benefits Tax (FBT) instalments
BAS can be lodged monthly, quarterly, or annually depending on the business size and turnover.
Understanding GST in Australia
GST (Goods and Services Tax) is a 10% tax applied to most goods and services sold or consumed in Australia. If your business has an annual turnover of AUD 75,000 or more, GST registration is mandatory. For non-profits, the threshold is AUD 150,000.
Once registered, businesses must:
- Charge GST on taxable sales
- Claim GST credits on business purchases
- Report GST collected and paid through BAS
Importance of BAS & GST Accounting for Australian Companies
Proper BAS and GST accounting is not just about compliance—it directly impacts your business finances.
1. Legal Compliance
Incorrect or late BAS lodgment can result in penalties, interest charges, and audits by the ATO.
2. Cash Flow Management
Accurate GST tracking helps businesses plan payments in advance and avoid cash flow issues.
3. Claiming Maximum GST Credits
Well-maintained records ensure you don’t miss out on eligible GST input tax credits.
4. Financial Transparency
Clear tax records improve reporting accuracy and support better business decisions.
BAS & GST Accounting Process Explained
Step 1: GST Registration
Register your business for GST through the Australian Business Register (ABR). Once registered, you must include GST in your pricing and invoices.
Step 2: Maintain Accurate Records
Keep proper documentation for:
- Tax invoices
- Purchase bills
- Sales receipts
- Bank statements
Digital accounting software makes this process easier and more reliable.
Step 3: Calculate GST
You need to calculate:
- GST collected from customers
- GST paid on business expenses
The difference determines whether you pay GST to the ATO or receive a refund.
Step 4: Prepare and Lodge BAS
Compile all tax information and lodge BAS online through:
- ATO Business Portal
- Registered BAS agents
- Accounting software
Step 5: Pay Tax or Claim Refund
Pay any outstanding tax by the due date or receive a GST refund if credits exceed liabilities.
Common BAS & GST Mistakes Businesses Should Avoid
Many Australian companies face penalties due to avoidable errors:
- Missing BAS lodgment deadlines
- Claiming GST on non-claimable expenses
- Incorrect GST classification (taxable, GST-free, input taxed)
- Poor record-keeping
- Not reconciling bank and GST data
Avoiding these mistakes saves time, money, and stress.
Role of Accounting Software in BAS & GST
Modern accounting tools simplify BAS and GST compliance. Popular features include:
- Automatic GST calculation
- Real-time financial reporting
- BAS-ready reports
- Bank reconciliation
- Secure cloud access
Using accounting software reduces human error and speeds up compliance.
Why Hire a Professional BAS & GST Accountant?
While some businesses manage BAS internally, professional support offers significant advantages.
Expertise & Accuracy
Professional accountants understand ATO rules and ensure error-free reporting.
Time Savings
Outsourcing BAS allows business owners to focus on growth instead of paperwork.
Audit Support
Accountants help respond to ATO audits and compliance reviews.
Strategic Advice
Beyond compliance, professionals provide insights on tax planning and cost efficiency.
BAS & GST Accounting for Small vs Large Companies
Small Businesses
- Often lodge BAS quarterly
- Benefit greatly from bookkeeping and BAS agent services
- Require cash flow planning for GST payments
Medium & Large Companies
- Usually lodge monthly BAS
- Handle complex GST transactions
- Require advanced accounting systems and expert oversight
Each business size requires a tailored BAS & GST accounting approach.
BAS Lodgment Due Dates (General Guide)
- Quarterly BAS:
- Q1 (Jul–Sep): 28 Oct
- Q2 (Oct–Dec): 28 Feb
- Q3 (Jan–Mar): 28 Apr
- Q4 (Apr–Jun): 28 Jul
- Monthly BAS: 21st of the following month
Meeting deadlines is critical to avoid fines and interest.
Benefits of Outsourcing BAS & GST Accounting
Outsourcing is increasingly popular among Australian companies due to:
- Lower operational costs
- Access to skilled professionals
- Reduced compliance risk
- Scalable accounting support
- Improved financial accuracy
It is especially beneficial for startups and growing businesses.
How to Choose the Right BAS & GST Accounting Service
Before hiring an accounting service, consider:
- Experience with Australian GST laws
- Registered BAS agent credentials
- Use of modern accounting software
- Transparent pricing
- Data security and confidentiality
Choosing the right partner ensures long-term compliance and peace of mind.
Future of BAS & GST Compliance in Australia
The ATO continues to push digital compliance through:
- Real-time reporting
- Increased data matching
- Cloud-based accounting integration
Businesses that adopt digital accounting practices early will benefit from smoother compliance and reduced audit risk.
Conclusion
BAS & GST accounting for Australian companies is a critical function that ensures legal compliance, financial stability, and operational efficiency. Whether managed in-house or outsourced, maintaining accurate GST records and timely BAS lodgment is essential for business success in Australia.
By understanding BAS requirements, using the right accounting tools, and seeking professional support when needed, Australian companies can stay compliant, reduce tax risks, and focus on sustainable growth.