When do I need to register for GST as a sole trader?

You must register for GST within 21 days of your current or projected gross business turnover reaching $75,000 AUD. If you provide taxi or ride-sourcing services, you must register regardless of your income. Businesses earning under $75,000 can register voluntarily to claim back GST credits on operational tools and materials.

How often do small businesses lodge BAS in Australia?

Most Australian small businesses with a turnover under $20 million lodge their BAS quarterly, with due dates on the 28th of October, February, April, and July. Businesses can elect to lodge monthly if turnover exceeds $20 million or to expedite refunds, while eligible micro-businesses earning under $75,000 may report annually.

Can I claim GST on all my trade business expenses?

You can only claim GST credits on purchases used solely for business operations where GST was explicitly included in the price. You must hold a valid tax invoice for any purchase exceeding $82.50 AUD including GST. Mixed-use purchases, such as a dual-cab ute or personal mobile, require accurate percentage apportioning.

What happens if I make a mistake on my BAS lodgement?

You can correct minor BAS errors on your next activity statement if they fall within ATO debit error time and value limits. For net debit errors over $10,000 AUD or mistakes outside standard timeframes, you must lodge a formal revision for the original period to avoid potential general interest charges and penalties.

What records must I keep for BAS and GST compliance?

You must legally retain all financial records, valid tax invoices, receipts, and payroll documents for five years from the date you lodge your BAS. The ATO requires electronic or physical documentation that clearly identifies the supplier's ABN, the GST amount charged, the date of supply, and the items purchased.

How do BAS and GST work for small businesses in Australia?

Understand BAS and GST for Australian tradies and small businesses. Learn mandatory ATO turnover thresholds, lodgement cycles, and tax credit claim rules.

Quick answer

GST is a 10 percent tax on taxable goods and services in Australia, mandatory for businesses with a turnover of $75,000 or more. The Business Activity Statement, or BAS, is the ATO form used quarterly or monthly to reconcile GST collected against input credits and remit net liabilities.

Skill level: General guidance
Time: Varies
Trade: Accounting & Business Structures
Updated: 4 November 2026

Tools you will need

Xero Standard Plan - Cloud Accounting Software
MYOB Business Pro - Small Business Bookkeeping Software
Intuit QuickBooks Online Plus - Accounting & BAS Preparation Software
Dext Prepare Business - Automated Receipt & Invoice Scanner App
Hubdoc - Digital Document Management & Data Extraction Tool
ATO Online Services for Business - Tax Agent Portal & Lodgement Platform

Why is understanding BAS and GST crucial for Australian small businesses?

BAS and GST are two of the most common compliance pressure points for Australian small businesses, sole traders and contractors. Understanding the basics helps you stay organised, avoid reporting errors and manage cash flow, but the right setup and reporting approach depends on how your business operates.

What are the key principles of BAS and GST for tradies?

GST is a tax on many goods and services, and BAS is one of the main ways businesses report it to the ATO. If your business is registered for GST, you generally collect GST on taxable sales, claim GST credits on eligible business purchases, and report the net amount through your Business Activity Statement.

Not every business has to register for GST straight away. Whether registration is required depends on factors such as your turnover and business activities, and some businesses choose to register voluntarily. The ATO sets the rules, and the current thresholds and requirements should always be checked there.

Your BAS can include more than just GST. Depending on your registrations and obligations, a BAS may also include PAYG withholding, PAYG instalments and other amounts. That is why BAS preparation is not just “adding up GST” — it needs to match your registrations, payroll setup and ATO reporting obligations.

Good bookkeeping is the foundation of accurate BAS lodgements. Clean transaction coding, correct tax settings in your accounting software, and proper handling of items like private use, mixed-purpose expenses, deposits and refunds all affect the numbers reported. Small coding errors can flow through every quarter if they are not picked up early.

Deadlines and record-keeping matter. BAS is usually lodged on a regular cycle set by the ATO, and missing due dates can create avoidable stress, interest or penalties. The ATO and the Tax Practitioners Board (TPB) both expect businesses to keep proper records to support what has been reported.

What does an accounting specialist review for BAS and GST compliance?

Whether you should be registered for GST, and from what date. This can depend on turnover, the nature of your services, contractor arrangements, and whether some income is GST-free, input taxed or outside the GST system.

How your sales and expenses should actually be coded. A qualified accountant or registered BAS agent would review your invoicing, supplier bills, bank feeds and chart of accounts to see whether GST has been applied correctly and consistently.

Whether your BAS obligations match your broader setup. That includes your business structure, payroll obligations, PAYG registrations, super processes and whether your software setup reflects how the business really operates.

How BAS fits into your cash flow. A specialist will often look beyond compliance and assess whether GST collections are being set aside properly, whether margins support your current pricing, and whether reporting cycles are causing cash pressure.

Any historical errors or clean-up work. If prior BAS lodgements may be wrong, a professional can assess what needs correcting and how to deal with the ATO in the proper way, rather than guessing or compounding the issue.

Common Costly Mistakes

Registering late, or assuming GST registration is optional when it may no longer be.

Treating all income and expenses as if they have the same GST treatment.

Using accounting software defaults without checking whether the tax codes are actually right.

Lodging BAS based on bank balance movements rather than reliable bookkeeping records.

When To Get Professional Help

DIY BAS often stops making sense once you have staff, mixed types of income, growing turnover, or uncertainty about GST treatment on what you sell or buy. It is also worth getting help if your records are behind, your BAS figures do not seem to match your profit, or you are worried past lodgements may be incorrect.

Talk To A Specialist

If BAS and GST are taking too much time or creating uncertainty, a short conversation with a specialist can help you understand what is required and where the risks are. You can book a free accounting discovery call here: /finance/enquire?service=accounting

Frequently Asked Questions

Do I need to register for GST as a sole trader in Australia?

Not always. GST registration depends on factors such as your turnover and the type of business activities you carry on, and the ATO sets the current rules and thresholds. Some sole traders register voluntarily, but whether that makes sense depends on their circumstances.

What is the difference between BAS and GST?

GST is the tax itself, while BAS is the reporting form used to tell the ATO about GST and sometimes other obligations as well. Many business owners use the terms together, but they are not the same thing. Your BAS may include GST, PAYG withholding, PAYG instalments and other items depending on your registrations.

How often do small businesses lodge BAS?

That depends on how your business is registered with the ATO and the reporting cycle that applies to you. Many small businesses lodge regularly throughout the year, but the exact frequency can vary. It is important to check your ATO correspondence or online services so you work to the correct due dates.

Can I claim GST on all my business expenses?

No. You can generally only claim GST credits on eligible business purchases where GST has actually been charged and where you hold the right tax invoice or records. Some expenses have different treatment, and private or mixed-use purchases need careful handling.

What happens if I make a mistake on my BAS?

The right response depends on the size and type of the error, and whether it relates to the current period or an earlier one. Some mistakes can be corrected in a later BAS, while others may require a different approach. If you are unsure, it is sensible to speak with a registered BAS agent, accountant or tax professional and check ATO guidance.

Important — General Information Only

This information is general in nature only and is not personal accounting, BAS, GST or business structures advice. It does not take into account your objectives, financial situation or needs, and you should consider your own circumstances and seek advice from a qualified accountant, registered BAS agent or registered tax practitioner before acting. For authoritative guidance, refer to the ATO, ASIC where relevant, the Tax Practitioners Board, CPA Australia and Chartered Accountants ANZ.

Frequently asked questions

When do I need to register for GST as a sole trader?: You must register for GST within 21 days of your current or projected gross business turnover reaching $75,000 AUD. If you provide taxi or ride-sourcing services, you must register regardless of your income. Businesses earning under $75,000 can register voluntarily to claim back GST credits on operational tools and materials.
What is the difference between BAS and GST?: GST is a 10 percent broad-based tax added to most goods and services, while a Business Activity Statement (BAS) is the mandatory ATO reporting form. Your BAS reports collected GST, claims input tax credits, and covers other business obligations including PAYG withholding, PAYG instalments, and fringe benefits tax.
How often do small businesses lodge BAS in Australia?: Most Australian small businesses with a turnover under $20 million lodge their BAS quarterly, with due dates on the 28th of October, February, April, and July. Businesses can elect to lodge monthly if turnover exceeds $20 million or to expedite refunds, while eligible micro-businesses earning under $75,000 may report annually.
Can I claim GST on all my trade business expenses?: You can only claim GST credits on purchases used solely for business operations where GST was explicitly included in the price. You must hold a valid tax invoice for any purchase exceeding $82.50 AUD including GST. Mixed-use purchases, such as a dual-cab ute or personal mobile, require accurate percentage apportioning.
What happens if I make a mistake on my BAS lodgement?: You can correct minor BAS errors on your next activity statement if they fall within ATO debit error time and value limits. For net debit errors over $10,000 AUD or mistakes outside standard timeframes, you must lodge a formal revision for the original period to avoid potential general interest charges and penalties.
What records must I keep for BAS and GST compliance?: You must legally retain all financial records, valid tax invoices, receipts, and payroll documents for five years from the date you lodge your BAS. The ATO requires electronic or physical documentation that clearly identifies the supplier's ABN, the GST amount charged, the date of supply, and the items purchased.

Written by Ledger, the Accounting & Business Structures specialist at Aus.Tools.