The complete GST guide for Aussie tradies

Registering for GST#

Registration stops being a choice at $75,000 of GST turnover. Turnover means gross income before expenses, not profit, which catches people out: a business that grossed $80,000 and cleared $30,000 is over the line.

The voluntary case turns on who your customers are. A business client claims the GST back and is indifferent to it. A householder cannot, so registering raises your effective price by 10% against an unregistered competitor quoting the same job. That is the whole trade-off, and it is worth doing the sum before deciding.

1. 1

   Get an ABN if you do not have one

   Free, through the Australian Business Register. You cannot register for GST without it.

2. 2

   Register for GST

   Through the ABR, ATO online services, or your registered agent.

3. 3

   Choose cash or accrual

   Cash accounting means GST follows the money. Most small trade businesses use it, because it means you are not remitting GST on an invoice that has not been paid yet.

4. 4

   Choose your reporting cycle

   Quarterly is standard for a small business. The cycle is set at registration and shown on your BAS.

ATO: registering for GST

Charging it on your work#

GST is 10% added to your price. The direction matters, because adding 10% and removing 10% are not inverse operations and getting them confused is the single most common arithmetic error in the trade.

What you send matters as much as what you charge. A tax invoice is a specific document, not a nicer-looking invoice, and you may only head one "tax invoice" if you are actually registered.

• The words Tax invoice, your business name and your ABN.
• The date, and enough detail to identify what you did.
• The GST amount, or the line "Total price includes GST".
• Show GST separately on quotes too, so the client is not surprised at invoicing.

The free tax invoice generator applies all of that, and the quote generator does the same for the price you send first. ATO: tax invoices.

What is actually GST-free#

This section exists because the belief that parts of a trade invoice are GST-free is common and expensive. GST-free is not a judgement call about whether something feels like a service. It is a defined list the ATO publishes, and it covers things like basic food, most medical and health services, most education, childcare, and exports.

The place GST-free genuinely turns up in a trade business is on the buying side, not the selling side. Some of what you purchase has no GST in it, which means there is no credit to claim on it no matter how legitimately it was a business expense.

Claiming credits on what you buy#

Two conditions, both easy to miss: the supplier has to be registered, and the use has to be business use. "It was a business expense" is not by itself enough.

Mixed-use items are where audits land. A ute at 80% business use gives you 80% of the GST, and the number has to be defensible: a logbook, a pattern of jobs, something other than a figure that felt about right at quarter end.

Reporting it each quarter#

Each quarter you report the GST you collected, the credits you are claiming, and pay or receive the difference. The next standard quarterly BAS falls due 28 October 2026, covering July to September 2026.

Due dates, the lodgment concession for going through a registered agent, and what late lodgement costs are all on the quarterly BAS page, which works them out from the ATO rule rather than listing them. ATO: BAS due dates.

Worked examples by trade#

The rules are the same for everyone. What differs is the shape of a typical job, and the shape is what decides whether a quarter leaves you owing money or owed it.

Electrical work: materials carry the credit#

Plumbing: the call-out fee is taxable too#

Building: GST follows the progress claim#

Landscaping: only what you supply#

The mistakes that cost money#

Almost none of these are arithmetic. They are habits, and each one has a cheap fix that has to happen at the time rather than at quarter end.

• Spending the GST. It lands in the same account as everything else and looks identical to revenue. Move it, or at least know the number.
• Losing the supplier docket. Not a small loss. It is the entire credit on that purchase.
• Treating part of an invoice as GST-free. Covered above, and the shortfall is yours.
• Guessing the business-use split. A number you cannot substantiate is a number you may have to give back.
• Registering late. The liability backdates to when you crossed the threshold, and you will not be able to go back and charge those clients GST.
• Not lodging because you cannot pay. Lodging and paying are penalised separately, so silence is the worst of the options.

Every one of them is a record-keeping problem wearing a deadline's clothes. Chippie calculates GST on each quote and invoice line as you write it, lets you mark lines GST-free where that genuinely applies, and keeps a running quarterly position so the quarter is visible before it closes. Lodgement still goes through you, your accountant, or Xero. ATO: when you cannot claim a GST credit.