GST registration is one of the first compliance decisions every Australian business faces. Get it wrong and you either miss out on input tax credits or owe the ATO backdated GST you never collected. Here's the complete guide for 2026.
1. The $75,000 Threshold
You must register for GST if your business has a GST turnover (gross income minus GST) of $75,000 or more in the current or previous 12-month period. For non-profit organisations, the threshold is $150,000.
Important: the test is based on projected turnover, not just historical. If you sign a contract that will push you over $75,000 in the next 12 months, you must register immediately — you can't wait until you actually hit the threshold.
2. Mandatory Registration Triggers
- Turnover exceeds $75,000 in any rolling 12-month period.
- Taxi or ride-sharing drivers — must register regardless of turnover (Uber, Ola, DiDi, etc.).
- Non-residents making sales connected to Australia — different rules apply; seek advice.
You have 21 days from the date you become aware (or should have become aware) that you've exceeded the threshold to register.
3. Voluntary Registration Benefits
Even if your turnover is below $75,000, registering voluntarily can make sense if:
- You have significant business purchases — you can claim back GST on equipment, software, rent, and supplies.
- Your clients are GST-registered businesses — they can claim input credits on your invoices, making you more competitive.
- You're in a startup phase — you're spending heavily upfront (fit-out, equipment, marketing) and want to recover the GST before you earn revenue.
However, if your clients are mainly consumers (not businesses), adding 10% GST to your prices may make you less competitive. Weigh this carefully.
4. What Happens If You Register Late?
If the ATO determines you should have been registered earlier, they can:
- Backdate your registration to when you first exceeded the threshold.
- Assess GST on all sales during the unregistered period — even if you didn't charge GST to customers.
- Apply penalties for failure to register (up to 75% of the GST shortfall in cases of intentional disregard).
The silver lining: you can also claim input credits for the backdated period if you have valid tax invoices.
5. Choosing Your BAS Reporting Cycle
When you register, you'll choose how often to lodge your BAS:
| Cycle | Who It Suits | Due Date |
|---|---|---|
| Monthly | Turnover >$20M or by choice | 21st of following month |
| Quarterly | Most SMEs (default) | 28th after quarter end |
| Annually | Turnover <$75k (voluntary registrants) | 28 Feb (or later with agent) |
Key Takeaways
- Register within 21 days of exceeding (or projecting to exceed) $75,000 turnover.
- Ride-share drivers must register regardless of turnover.
- Voluntary registration is worth it if you have high business costs or B2B clients.
- Late registration can result in backdated GST assessments and penalties.
- Choose quarterly BAS for most SMEs — it balances admin burden with cash flow management.