GST for Small Business: A Practical Guide

If you're starting or running a small business in Australia, understanding GST is one of the more mechanical but genuinely important parts of getting your finances right from day one. Get it wrong and you either overcharge customers, underpay the ATO, or miss out on credits you're entitled to — all fixable, but all avoidable with a clear understanding upfront.

Do you need to register for GST?

Registration is compulsory once your business has a GST turnover of $75,000 or more in a 12-month period ($150,000 for non-profit organisations). Below that threshold, registration is optional. Many small or part-time businesses choose to register anyway, particularly if most of their customers are other GST-registered businesses who can claim back the GST as a credit, making the extra 10% relatively painless for the end customer.

One important exception: if you're driving for a ride-sharing service (like Uber) or renting out short-term accommodation, you may need to register for GST regardless of your turnover, due to specific ATO rules for these industries.

How GST actually works for your business

Once registered, you charge GST (10%) on your taxable sales, collect it from customers, and remit it to the ATO. In return, you can claim back GST credits (input tax credits) on eligible business purchases and expenses — meaning you're not truly out of pocket for the GST on things you buy for the business, only on the net difference between GST collected and GST paid.

Business Activity Statements (BAS)

GST-registered businesses report and pay GST through a Business Activity Statement, generally lodged quarterly (though some very small businesses can opt for annual reporting, and larger businesses may need to report monthly). Your BAS also typically covers PAYG withholding for employees and PAYG instalments if applicable, making it a fairly central piece of small business compliance rather than a GST-only form.

What's GST-free vs input-taxed?

Not everything you sell necessarily attracts GST. Most basic food (though not all — prepared and restaurant food generally does attract GST), most medical and healthcare services, and most education services are GST-free, meaning you don't charge GST but can still claim input tax credits on related purchases. Financial services and residential rent are typically "input-taxed" instead — a subtly different category where you also don't charge GST, but generally can't claim input tax credits on related purchases either. Getting this distinction right matters for accurate BAS reporting.

Common mistakes small businesses make

• Forgetting to register when crossing $75,000 — the obligation to register starts from when you reasonably expect to exceed the threshold, not after you've already exceeded it, so don't wait for the BAS deadline to catch you out
• Pricing without accounting for GST — quoting a price as if it's your full revenue, then discovering 1/11th of it needs to go to the ATO, can quietly erode margins if not planned for from the start
• Missing input tax credits — not claiming GST credits on legitimate business expenses (equipment, software subscriptions, professional services) leaves money on the table every quarter
• Confusing GST-free with input-taxed — these categories are treated differently for input tax credit purposes, and mixing them up leads to reporting errors

Worked example: quoting a $1,000 job

If your business is GST-registered, a genuine $1,000 job (excluding GST) needs to be invoiced at $1,100 including GST. You keep the $1,000, and the $100 GST component gets remitted to the ATO (less any GST credits you're entitled to claim on expenses related to that job). If you instead quote $1,000 as your total invoice, you're really only keeping $909.09 — a subtle but meaningful difference many new business owners overlook.

Sources: ATO.gov.au GST registration and reporting guidance. This article is for informational purposes only and does not constitute tax or business advice. Always consult a registered tax agent or accountant for advice specific to your business.