How to Add GST to an Invoice (Australia)

Do I need to add GST to my invoice?

Only if your business is registered for GST. Registration is compulsory once your GST turnover reaches $75,000 in any 12-month period ($150,000 for non-profits). Taxi and rideshare drivers must register from their first dollar of income, whatever their turnover. Below the threshold you can register voluntarily, which lets you claim GST credits on business purchases.

• Registered for GST: add 10% GST to taxable sales.
• Not registered: issue a regular invoice with no GST line and no GST wording.
• Unsure: add up your turnover for the past 12 months and your expected turnover for the next 12. If either reaches $75,000, you need to register within 21 days.

Do I include GST on my invoices if I'm not registered?

No. A business that isn't registered for GST can't charge GST, and its paperwork must not use GST wording. If you've added GST by mistake, reissue the invoice without it and refund any GST amount the client has already paid. If you're close to the threshold, speak to your accountant or the ATO before your next invoice rather than after.

How to calculate GST on an invoice

GST in Australia is a flat 10%. There are two calculations, depending on whether your prices exclude or include GST.

Adding GST to a GST-exclusive price (× 1.1)

If you quote prices before GST, multiply the price by 10%, then add that on. A $500 job has $50 GST, so the invoice comes to $550. Multiplying by 1.1 gets you to the total in one step: $500 × 1.1 = $550.

Finding the GST in a GST-inclusive price (÷ 11)

If your price already includes GST, divide the total by 11 to find the GST. A $550 total contains $50 GST ($550 ÷ 11), so the price before GST is $500. Don't take 10% off the total. That gives $55, which is wrong, because the 10% was applied to the smaller pre-GST price.

GST-inclusive invoice vs GST-exclusive invoice

Both formats are fine. A GST-exclusive invoice lists each unit price before GST, then shows a subtotal, a GST line and the total. A GST-inclusive invoice lists prices that already include GST. It must then either show the GST figure or carry the statement "Total price includes GST". Retail and trade clients usually expect GST-inclusive totals. Business clients who claim GST credits often prefer the GST shown separately.

Mixed taxable and GST-free items

Some sales are GST-free. Common examples are most basic food, many health and medical services, some education courses, and exports. When one invoice mixes taxable and GST-free items, charge GST only on the taxable lines and mark which items are GST-free. For example, $400 of taxable labour plus $100 of GST-free items gives $40 GST and a $540 total, not $550.

Rounding GST to the cent

Round GST to the nearest cent, with half a cent rounding up. You can calculate GST on the invoice total or on each line, but use one method consistently. Rounding per line can occasionally differ by a cent from rounding the total, and either result is acceptable when applied consistently.

What a valid tax invoice must show

For a taxable sale over $82.50 (GST-inclusive), your customer is entitled to a tax invoice, and you must provide one within 28 days if they ask. It shows:

• The words "Tax Invoice" displayed prominently
• Your trading name and ABN
• The date of issue
• A description of each item, including quantity and price
• The GST payable, or the statement "Total price includes GST" when every item is taxable
• The total amount payable
• For sales of $1,000 or more (GST-inclusive), the buyer's identity or ABN

Invoicing overseas clients

Invoices to overseas clients are often GST-free. Goods exported from Australia usually qualify, and so do many services supplied to non-residents who aren't in Australia when the service is performed. The rules have conditions, so check the ATO guidance on GST-free exports, or ask your accountant, before you drop GST from an overseas invoice. Show the currency clearly and keep records of the export.

Changing an invoice after it's issued: adjustment notes

If the price changes after you've issued the invoice, because of a refund, a discount or a returned item, don't edit the original. Issue an adjustment note (a credit note) that references the original invoice number and shows the change in price and the change in GST. It works like the original document, just in reverse.

Keeping on top of your tax obligations

Charging GST adds a few tax obligations beyond the invoice itself: issue documents on time, keep copies, and lodge your BAS by the due date. Giving every invoice a unique invoice number and a clear unit price for each line makes reconciliation faster when BAS time comes around.

Reporting the GST you've invoiced on your BAS

The GST you add to invoices is money you collect on the ATO's behalf. Report your total sales at label G1 and the GST on sales at label 1A of your Business Activity Statement, then pay it to the ATO. If you account on a cash basis, report GST in the period you receive payment. On a non-cash (accrual) basis, report it in the period you issue the invoice. Keep invoices and records for five years.

Step by step

1. 1

   Open the invoice generator

   Start a new invoice in the free generator. You don't need an account.

2. 2

   Add your ABN and business details

   Enter your trading details, ABN and a unique invoice number so the document meets ATO rules.

3. 3

   List items and turn on GST

   Add each item with its unit price, then switch GST on. 10% is calculated on taxable lines, and you can leave GST-free lines at 0%.

4. 4

   Check the GST amount and total

   Confirm the subtotal, the GST line and the GST-inclusive total. For sales of $1,000 or more, add the buyer's name or ABN.

5. 5

   Add payment methods and send

   Include your payment methods, such as bank details or PayID, then download the PDF or email it.