Do I Need to Register for GST?

You must register for GST once your GST turnover reaches $75,000 in a 12-month period ($150,000 for non-profit organisations). Below that threshold, registration is optional. Turnover, not profit, is what's measured — it's your gross business income before expenses.

Once registered, you generally must add GST to your prices, issue proper tax invoices, lodge Business Activity Statements, and can claim GST credits on eligible business purchases.

GST turnover is measured on a rolling 12-month basis, and the ATO looks at it two ways:

• Looking back: your gross business income for the past 12 months.

• Looking forward: your projected income for the current month plus the next 11.

If either test reaches $75,000, registration becomes compulsory — and you have 21 days from becoming aware of it to register. This is why it's worth checking your rolling turnover regularly rather than only at tax time.

There are exceptions: taxi and ride-sourcing drivers (Uber, Ola, DiDi and similar) must register for GST from their very first trip, regardless of turnover.

A freelance consultant earns $68,000 in the year — no registration required. She then wins a new retainer client worth $2,000 a month. Her projected turnover for the next 12 months is now $92,000 — over the threshold, using the forward-looking test, even though her rolling 12-month total hasn't reached $75,000 yet. She has 21 days to register from the point that projection became clear.

This is the detail that catches people out: it's not just about what you've already earned. It's also about what you can reasonably see coming.

• You generally include GST in the price of most goods and services you sell.

• You issue tax invoices that meet ATO requirements.

• You lodge Business Activity Statements, usually quarterly, reporting GST collected and GST paid.

• You can claim GST credits on eligible business purchases — and if your credits exceed what you owe, you may receive a refund.

Some businesses register even while under the threshold. It can make sense if:

• your business expenses include significant GST, and voluntary registration lets you claim it back;

• your clients are mostly other GST-registered businesses, who are largely indifferent to the GST on your invoice because they can claim it back themselves; or

• you're growing quickly and want your systems and pricing ready before you're forced to register mid-year.

The trade-off is that once registered, you're generally expected to stay registered for at least 12 months, and you take on the ongoing admin of BAS reporting regardless of your turnover.

If you exceed the threshold and don't register, the ATO can backdate your registration — meaning you may owe GST on sales you've already made, potentially with interest and penalties, even if you never collected that GST from your customers in the first place.

• What has my business actually earned, gross, over the past 12 months?

• Based on confirmed work or contracts, what am I likely to earn over the next 12 months?

• Am I in an industry with no threshold at all, like ride-sourcing?

• If I'm below the threshold, would voluntary registration genuinely help me — or just add admin?

The Australian Government provides guidance on registering for GST and working out your GST turnover.

business.gov.au — Register for goods and services tax (GST) https://business.gov.au/registrations/register-for-taxes/register-for-goods-and-services-tax-gst

• you're approaching the threshold and want to confirm exactly when registration becomes compulsory;

• you're deciding whether voluntary registration makes sense for your situation;

• you think you may have already crossed the threshold without registering; or

• you want your pricing and invoicing set up correctly for GST from day one.

→ ABN, ACN, TFN and GST — What Do All These Numbers Actually Mean?

→ Understanding BAS — What Am I Actually Reporting and Paying?

→ GST Collected Isn't Really My Money — So How Should I Manage It?

SKC Accounting | Knowledge Centre | Knowledge Guide 004

Last reviewed: August 2026

General information only. This guide does not take into account your individual circumstances and is not a substitute for professional accounting, taxation, legal or financial advice.