Do you need to register for GST as a sole trader?

Last updated: July 2026

    Short answer: only once your turnover — not profit — hits $75,000 in any rolling 12-month period, or you expect it to. Below that, registration is your choice. Above it, it's compulsory, and the ATO doesn't wait for you to notice.
  

GST is one of the more misunderstood parts of running as a sole trader, mostly because the trigger is turnover rather than profit or take-home pay. A freelancer billing $80,000 a year with high expenses and modest actual earnings still crosses the threshold, because it's measured on what you invoice, not what you keep.

1. The $75,000 threshold, explained properly

You must register for GST once your GST turnover — your gross business income, excluding GST itself — reaches $75,000 in any 12-month period. This isn't a financial-year cutoff. It's assessed on a rolling basis: both your turnover for the past 12 months and your projected turnover for the next 12 months count. If you can see $75,000 coming, you're required to register before you get there, not after.

Not sure where you actually stand? Run your numbers through the threshold checker rather than guessing:

→ GST registration threshold checker

2. What changes once you're registered

You add 10% GST to your invoices for taxable sales
You lodge a Business Activity Statement (BAS) — usually quarterly — reporting GST collected and GST paid on business expenses
You can claim back the GST you've paid on business purchases (called GST credits)
Your invoices need to meet "tax invoice" requirements once sales are over $82.50 including GST

3. Below the threshold: registering is optional, not off the table

If you're under $75,000, you can choose to register voluntarily. There's a real case for and against it, and it genuinely depends on who your clients are:

Registering early can help if

Most of your clients are GST-registered businesses who can claim the GST back, so it costs them nothing extra
You have significant upfront expenses (equipment, software) and want to claim GST credits on them
You want your invoices to look more established to corporate clients

Staying unregistered can help if

Your clients are mostly individuals or small businesses who can't claim GST back — registering just makes you 10% more expensive to them
You want to avoid the ongoing admin of quarterly BAS lodgements
Your turnover is well under the threshold and unlikely to grow quickly

4. How to register

If you already have an ABN, you can add GST registration to it directly through the ATO's Business Portal, myGov (linked to the ATO), or via a registered tax agent. It takes effect from the date you choose or the date you're required to register from, whichever applies. There's no fee to register.

5. The most common mistake

The most common issue isn't forgetting to register — it's failing to notice turnover has crossed the threshold partway through the year, then owing GST retroactively on sales that were never priced to include it. If your income is trending up, it's worth checking your rolling 12-month turnover regularly rather than only at tax time, so you can register (and adjust your pricing) before you're forced to absorb the 10% yourself.

Work out what registering would actually mean for you

Once you know your GST position, see how it interacts with your income tax, Medicare levy, and quarterly instalments.

Read the full sole trader tax guide →