GST Invoicing for Tradies: What Every Invoice Needs

A short, plain guide to invoicing the right way in Australia. What counts as a valid tax invoice, when GST kicks in, and how to get the paperwork out before you leave the driveway.

When do you actually have to register for GST?

The line most tradies watch is the $75,000 turnover mark. Once your business turns over $75,000 or more in a rolling twelve months, or you expect to hit that in the coming year, you have to register for GST with the ATO. Turnover means your total sales, not your profit, so it adds up faster than people think. A sole trader doing a few kitchens and a run of maintenance work can cross it inside a busy quarter.

You can register before you hit the threshold if you want to, and some tradies do so they can claim GST credits on tools, the ute and materials from day one. Others hold off until they have to, to keep the pricing simple for cash-job customers. There is no single right answer, and it depends on your numbers, so this is the point to have a quick chat with your accountant rather than copy what the bloke next door did.

Once you are registered, you charge 10 per cent GST on top of your prices and you send that GST to the ATO, usually through your Business Activity Statement. You also get to claim back the GST you paid on business purchases. If you are not registered, you do not charge GST at all, and your invoice is just an invoice, not a tax invoice.

What a valid tax invoice has to show

The ATO is specific about this, and it matters because your customer needs a valid tax invoice to claim their own GST credit. If yours is missing bits, a business customer can bounce it straight back to you and hold up payment. Here is what a compliant tax invoice for a sale of $82.50 or more (including GST) needs to carry.

• The words Tax invoice, clearly, usually at the top.
• Your business or trading name.
• Your ABN.
• The date you issued it.
• A description of what you did or supplied, with quantities where it makes sense.
• The GST amount, either shown as a separate line or with a note that the total includes GST.
• The buyer's identity or ABN once the invoice is $1,000 or more (including GST).

For anything under $82.50 including GST you can get away with less, but honestly it is easier to make every invoice look the same. Set up one clean template and you never have to think about which rules apply to which job.

Tax invoices are not quotes, and the difference matters

A quote is your offer before the work. It says what you will do and roughly what it will cost, and the customer can take it or leave it. A tax invoice is the bill after the work, and it is a formal record for both of you at tax time. They are different documents doing different jobs, so do not just relabel a quote and send it as the invoice.

The trap is copying an old quote, changing the heading and firing it off. If the scope changed on site, the numbers are now wrong, and if you forgot to add the GST line or your ABN, it is not a valid tax invoice at all. Build the invoice from what you actually did, confirm the final figures, and check the GST is calculated on the real total. A quote that turned into three variations should produce an invoice that reflects all three.

The mistakes that bite at BAS time

Most invoicing pain shows up months later when you sit down to do your BAS and the numbers do not line up. A few habits cause most of it.

Leaving GST off invoices you should have charged it on. If you were registered and forgot the GST, that 10 per cent still has to go to the ATO, so you either wear it or chase the customer for more after the fact. Neither is fun. The reverse also happens: charging GST when you were not registered, which you are not allowed to do.

Mixing up GST-free and taxable items. Most trade work is taxable, but the odd supply can be treated differently, and if you are unsure, that is an accountant question, not a guess. Missing ABNs and no-tax-invoice receipts are another one. If you cannot show a valid tax invoice for a business purchase, you may not be able to claim the GST credit on it, so keep the receipts as you go rather than hunting for them in the glovebox in July.

Rounding and maths slips round out the list. When you total by hand at the end of a long day, it is easy to get the GST a dollar or two out. Software that calculates it for you takes that whole category of error off the table. Whatever you use, keep your records, because the ATO expects you to hold onto invoices and receipts for five years.

Getting the invoice out while you are still on site

The best invoice is the one you send before you drive off. Every hour between finishing the job and sending the bill is an hour the customer forgets how good the work was and how much they owed. Invoice on the spot and you get paid faster, full stop.

That is hard to do with a paper book and a spreadsheet you only open at night. It is a lot easier when the job you quoted turns into the invoice with a couple of taps, the GST is worked out for you, and your ABN and details are already sitting in the template. ServicePilot handles the quote-to-invoice flow and card payments in one place, so you can raise a compliant tax invoice from your phone in the driveway. You can see how the invoicing and payments features fit together if you want the detail.

Whatever tool you land on, the goal is the same. A tidy, valid tax invoice, out fast, with the GST correct and the money in your account before the next job starts.

Frequently asked questions

Do I have to charge GST if I earn under $75,000?
No. If your turnover is under the $75,000 threshold and you have not chosen to register, you do not charge GST and your invoices are not tax invoices. Once you cross the threshold, or expect to, you must register and start charging it.

What if I forget to put my ABN on an invoice?
Without an ABN it is not a valid tax invoice, and a business customer cannot claim their GST credit from it. Worse, if you supply goods or services to a business without an ABN, they may be required to withhold tax from your payment. Put your ABN on every invoice you send.

Can I just send my quote again as the invoice?
Not safely. A quote and a tax invoice are different documents, and the final scope often changes on site. Build the invoice from the work you actually did, confirm the totals, and make sure it has the tax invoice heading, your ABN and the GST amount.