Do I charge GST? The $75k question

Under $75,000 turnover, GST is optional. Cross it and you've got 21 days to register. Miss that window and the ATO can claim GST on sales you never charged it on, out of your pocket.

The $75,000 rule, properly

The threshold is $75,000 of turnover over a rolling 12 months. Rolling is the word people miss. It's not "this financial year", it's any 12-month stretch, looking backwards and forwards. If the last 11 months plus a big job this month tips you over, you're over.

And it's turnover, not profit. What you invoiced, not what you kept. Plenty of tradies clear $75k in sales while making far less after materials, and the rule counts the sales.

Crossed it? The clock's running

You have 21 days from crossing the threshold to register. Registration itself is free, but you need an ABN first.

Here's why the deadline has teeth. Register late and the ATO can backdate your registration to when you should have signed up. That means GST is owed on everything you sold from that date, even though you never added it to those invoices. Roughly one-eleventh of those sales, gone, because you can't exactly ring old customers asking for 10% more. Watch your rolling total, and move the week you cross it.

Under $75k? Your call

Below the threshold, registering is voluntary. Some tradies register early to claim back the GST on tools, materials and the ute. The trade-off is your prices carry 10% GST, which a homeowner can't claim back, and you take on BAS lodgements. There's no universal right answer, which is exactly the kind of thing an accountant earns their fee on.

What changes on your invoices

Once registered, your invoices become tax invoices: the words "Tax invoice" at the top, your ABN, and the GST shown as its own amount or a note that prices include 10% GST. The full field list is in what has to be on a tax invoice. Not registered? Then it's plain "Invoice", no GST line at all - and the difference between your ABN and GST is worth two minutes if they're blurring together.

General information only - check the ATO or your accountant for your own situation.