How to Add GST to an Invoice (Australia)

If you're registered for GST in Australia you must add 10% GST to your taxable sales and issue a valid tax invoice. Here's exactly when to charge GST, how to calculate it, and what your invoice must show — plus how to do it automatically for free.

Written by InvoiceSonic Editorial Team · Updated 5 June 2026

Do I need to add GST to my invoice?

You only charge GST if your business is registered for GST. Registration is compulsory once your annual GST turnover reaches $75,000 (or $150,000 for non-profits); below that you can register voluntarily. If you're not registered, you must NOT add GST or call your document a "Tax Invoice".

  • Registered for GST → add 10% GST and issue a tax invoice.
  • Not registered → issue a regular invoice with no GST line and no "Tax Invoice" wording.
  • Not sure → check whether your turnover is at or above $75,000 over any rolling 12 months.

How to calculate GST (the 10% rule)

GST in Australia is a flat 10%. To add GST to a GST-exclusive price, multiply by 1.1 — e.g. $100 × 1.1 = $110 total. To find the GST already inside a GST-inclusive price, divide the total by 11 — e.g. $110 ÷ 11 = $10 GST.

If every line on your invoice is taxable, GST is simply 10% of the subtotal. Our generator does this automatically when you switch the GST toggle on, so you never have to do the maths by hand.

What a GST tax invoice must show

  • The words "Tax Invoice"
  • Your business name and ABN
  • The date of issue
  • A description of the goods or services
  • The GST amount (or a statement that the total includes GST)
  • The total price
  • For sales over $1,000 — the buyer's identity or ABN

Invoicing without GST

If you aren't registered for GST, create a normal invoice: your ABN, business name, date, a description, and the total — with no GST line and without the words "Tax Invoice". In our generator, just leave the GST toggle off.

Step by step

  1. 1

    Open the invoice generator

    Start a new invoice in the free generator.

  2. 2

    Add your ABN and business details

    Enter your business name and ABN so the document qualifies as a tax invoice.

  3. 3

    Turn on GST

    Switch the GST toggle on — 10% GST is calculated automatically on your taxable line items.

  4. 4

    Check the GST line and total

    Confirm the GST amount and GST-inclusive total are correct.

  5. 5

    Download or send

    Download the GST tax invoice as a PDF or email it to your client.

Australian tax invoice requirements

A valid Australian tax invoice must show the words “Tax Invoice”, your business name and ABN, the date of issue, a description of the goods or services, the GST amount (or a statement that the total includes GST), and the total price. For sales over $1,000 you must also include the buyer’s identity or ABN.

Create a free invoice

Or use our free invoice generator to start from scratch.

FAQ

Do I have to add GST to every invoice?

Only if you're registered for GST, and only on taxable sales. Some sales are GST-free (e.g. certain food, health and education). If you're not registered, you never add GST.

How do I work out the GST in a price that already includes it?

Divide the GST-inclusive total by 11. For example, $220 ÷ 11 = $20 GST, leaving $200 before GST.

Can I charge GST without an ABN?

No. You need an ABN to register for GST, and a valid tax invoice must show your ABN. Without an ABN, a payer may also have to withhold 47% of the payment under PAYG rules.

What if I'm not registered for GST?

Issue a standard invoice with no GST line and don't use the words "Tax Invoice". You can register voluntarily to claim GST credits on purchases if it suits your business.

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