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GST Registration: $75,000 Threshold and the 21-Day Rule

Updated 17 October 2026 · General information · 3 min read

General information, not tax, legal or financial advice. We are not the ATO and are not a registered tax or BAS agent. Check ato.gov.au or ask an agent. Sources read on 17 October 2026. Dates and amounts after that are expected. Examples use made-up numbers. This page contains no affiliate links.

Short answer: The ATO says you must register for GST when your GST turnover reaches $75,000 (the GST threshold), or when you start a business and expect to reach it in the first year, and you must register within 21 days of becoming required to. You need an ABN first.

When you must register (ATO, page updated 14 September 2026)

• GST turnover of $75,000 or more ($150,000 for non-profits);
• new business expecting to reach the threshold in the first year;
• taxi or limousine travel, including ride-sourcing, regardless of turnover;
• income through the sharing economy or digital platforms (the ATO gives food delivery as an example; see its sharing economy page);
• if you want to claim fuel tax credits. Otherwise registration is optional; if you choose to register, you generally must stay registered at least 12 months.

How turnover is worked out

Total business income (not profit), minus GST included in sales, sales to associates that aren't for payment and aren't taxable, sales not connected with your enterprise, input-taxed sales and sales not connected with Australia. You reach the threshold if either:

• current turnover (this month plus previous 11) is $75,000 or more; or
• projected turnover (this month plus next 11) is likely to be $75,000 or more. ATO example: a sole trader whose current turnover is $31,170 still has to calculate projected turnover each month. If current turnover is at or above the threshold you needn't register if the ATO is satisfied projected turnover will stay below it.

If you don't register

You may have to pay GST on sales since the date you were required to register, even if you didn't charge GST, plus penalties and interest. Backdating a registration is limited to 4 years and is requested by phone.

How to register

Through Online services for business, by phoning the ATO business line, or via your registered tax or BAS agent. After registering you lodge a BAS (key dates).

FAQ

Does it apply to hobby income?

Only if it is an enterprise; not covered here.

Can I register early?

Yes, it's optional below the threshold, with the 12-month minimum.

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