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Educational Guide

GST Registration in Australia:
Do You Need to Register?

Knowing when and how to register for GST is one of the first major decisions for any Australian small business or sole trader. Get it wrong and you risk ATO penalties. Or miss out on valuable GST credits.

R.

Written by Rob, founder of AusCalc

Australian small business owner. Checked against current ATO published rates. Updated July 2026. About AusCalc

The $75,000 GST Threshold

The general rule in Australia is that you must register for GST if your business turnover reaches $75,000 in any 12-month period. This applies whether the turnover is currently at that level or is projected to be in the next 12 months.

It is crucial to understand that turnover means your gross income before expenses. Not your final business profit. Even if your expenses are high and your profit is low, the $75,000 threshold applies to the total amount you invoice.

GST Turnover = Total Sales (excluding GST) in any 12-month period

If you haven't registered and your turnover passes the threshold, you have 21 days to register with the ATO and start collecting GST.

How to Register for GST

Registering for GST is a relatively simple process that can be completed through multiple channels:

  • ABN First: Ensure you have an active Australian Business Number (ABN).
  • Log In: Access the ATO Business Portal or your myGov account linked to your business.
  • Apply: Select "Register for GST" and provide the required business details.
  • Lodgement Cycle: Choose how often you will lodge your BAS (typically quarterly for small businesses).
  • Accounting Method: Select either Cash or Accruals accounting.

Tip: Most small businesses choose the Cash basis because it means you only account for GST when you actually receive or pay the money, helping significantly with cash flow management.

What You Must Do Once Registered

Once your registration is active, your business takes on several ongoing legal obligations:

Add GST: Add 10% GST to all of your taxable sales.
Tax Invoices: Issue valid tax invoices for any sales over $82.50.
Lodge BAS: Submit your Business Activity Statement on time.
Remit Net GST: Pay the net GST amount to the ATO.

Warning: If you forget to register after crossing $75,000, the ATO can back-date your registration and make you liable for GST you should have collected. Even if you didn't charge it to your customers.

GST Credits. Claiming Back What You Pay

The main advantage of being GST registered is your ability to claim input tax credits. This means you can claim back the GST you pay on your business purchases, effectively reducing the cost of your equipment, software, and overheads by 1/11th.

For example, if you buy a computer for $1,100 (which includes $100 GST), you can claim that $100 back as a credit on your next BAS, directly reducing your overall GST liability to the ATO.

Remember: You must keep a valid tax invoice from the supplier for any purchase over $82.50 to claim these credits legally.

BAS Lodgement and Payment

Most small businesses lodge their BAS quarterly. The standard due dates are:

  • Quarter 1 (Jul-Sep): Due 28 October
  • Quarter 2 (Oct-Dec): Due 28 February
  • Quarter 3 (Jan-Mar): Due 28 April
  • Quarter 4 (Apr-Jun): Due 28 July

Late lodgement penalties apply if you miss these dates, currently one penalty unit ($364) per 28-day period for small businesses.

Voluntary GST Registration. Is It Worth It?

Even if your turnover is under $75,000, you can choose to register voluntarily.

It is worth it if: You have high initial setup costs (to claim GST credits), your customers are other businesses who don't mind paying GST, or you want your business to appear larger and more established.

It is usually not worth it if: Your customers are private individuals who cannot claim credits (making your prices 10% more expensive than competitors), or your business expenses are extremely low.