GST registration: the $75,000 threshold and the voluntary registration decision

GST is a broad-based tax of 10% on most goods, services and other items sold or consumed in Australia. Registered businesses generally include GST in the prices they charge and claim credits for the GST in the price of what they buy for the business. Whether you must join that system turns on your GST turnover — plus a handful of rules that apply regardless of turnover.

GST turnover is your gross business income — not your profit — minus a specific set of amounts:

• GST included in sales to your customers
• sales to associates that are not for payment and are not taxable
• sales not connected with an enterprise you run
• input-taxed sales
• sales not connected with Australia

You reach the threshold if either test is met: your current GST turnover — the current month plus the previous 11 months — totals $75,000 or more ($150,000 for non-profits), or your projected GST turnover — the current month plus the next 11 months — is likely to be $75,000 or more ($150,000 for non-profits).

If you are not registered, the ATO expects you to check each month whether you have reached, or are likely to exceed, the threshold. If you are a member of a GST group, your turnover includes the other group members’ turnover but excludes transactions between members.

Projected turnover has its own exclusions: amounts from selling a business asset (such as a capital asset), and sales made solely because you are ceasing your enterprise or substantially and permanently reducing its size or scale, are not counted. That produces a useful nuance — even if your current turnover is at or above the threshold, you are not required to register if your projected turnover will stay below it, for example where a one-off asset sale inflated the past 12 months.

Once you are required to register, you must do so within 21 days. You need an ABN first, you only register once even if you run more than one business, and you can register through Online services for business, by phone on 13 28 66, or through a registered tax agent or BAS agent.

The cost of missing it is structural, not just administrative: if you do not register when required, you may have to pay GST on the taxable sales you made since the date you were required to register — even though you never added GST to those prices — so the GST comes out of your own takings rather than being passed on to customers. Penalties and interest may also apply.

Registration can be backdated, but the window is limited: unless there is fraud or evasion, the ATO cannot backdate a registration by more than 4 years, and you are not required to be registered before that date.

If none of the mandatory triggers apply, registration is optional — and if you register voluntarily, you generally must stay registered for at least 12 months. The decision is a genuine trade-off, and the ATO’s rules define both sides of the ledger.

What you gain. Only registered entities can claim GST credits on business purchases — generally where:

• the purchase is solely or partly for your business (and does not relate to making input-taxed supplies)
• the price included GST
• you provide or are liable to provide payment
• you hold a tax invoice for purchases of more than $82.50.

Credits apply only to the business-use portion, and a 4-year time limit applies to claiming them. GST registration is also the gateway to fuel tax credits. If equipment purchases are part of the picture, see our companion resource on the instant asset write-off status for 2026-27.

What it costs. You must include 10% GST in the price of your taxable sales, lodge activity statements on an ongoing cycle, and generally remain registered for at least 12 months even if it stops suiting you. If you are unregistered (and not required to register), the flip side is simple: no GST in your prices, and no GST credits on your purchases.

Who your customers are usually decides it. When your customers are mostly GST-registered businesses, they can generally claim credits for the GST you charge, so registering may cost you little competitively. When you sell mainly to consumers, adding GST means either a real price increase for them or a margin cut for you. Neither answer is universally right — it depends on your numbers and circumstances.

Registration brings a lodgement rhythm: once registered, you must lodge a business activity statement. The cycle depends on turnover and, in some cases, on choice.

Reporting itself is lighter than many owners expect: Simpler BAS is the default for GST turnover under $10 million — only total sales (G1), GST on sales (1A) and GST on purchases (1B) are reported. Businesses at $10 million or more use full reporting, and some under $10 million pay quarterly GST instalments and report annually. If a due date falls on a weekend or public holiday, the next business day applies.

Cycles can be changed: elect early in a lodgement period (such as the first month of a quarter or the start of the financial year) and the new cycle can generally start straight away; otherwise it takes effect from the next quarter or year, and you may be ineligible if you changed cycles within the last 12 months. Our BAS lodgement service manages the cycle, the due dates and the first BAS after registration; for the wider set-up questions, see our small business accounting service.