Do I Need to Include GST on My Invoice?

Only if you are registered for GST. GST appears on an invoice solely because the business issuing it is registered for GST with the ATO; whether you are registered is the single decision that determines what your invoice must (and must not) show.

In Australia, GST registration is compulsory once your GST turnover reaches $75,000 or more in a 12-month period ($150,000 or more for non-profit organisations). GST turnover means your gross business income, not your profit, measured over the current month plus the previous 11 months. Once you hit the threshold you must register within 21 days, and you need an ABN first. Below the threshold, registration is voluntary, so it is your choice whether GST applies to your invoices at all. The decision is binary: you are either registered (GST applies) or you are not (it does not). There is no in-between.

When you MUST include GST:

When you must NOT include GST:

A separate layer sits on top of registration: some supplies are GST-free even for registered businesses. Most basic foods, certain health and medical services, some education courses, and exports are generally GST-free. If you are registered and you sell a GST-free item, you still issue a Tax Invoice with your ABN, but you charge no GST on that item and the invoice should make the GST-free status clear (no GST line, or a zero GST amount). Invoices to international clients for exported goods or services are usually GST-free on the same basis, provided the export conditions are met.

Sales to overseas customers are a common source of confusion: being registered does not automatically mean every invoice carries GST, because the export itself may be GST-free. The registration decision controls whether GST can apply; the nature of the supply then controls whether it actually does.

InvoiceSonic lets you toggle GST on or off per invoice. Switch it on and the template adds the 10% calculation, labels the document a Tax Invoice, and shows the GST separately; switch it off and it produces a clean GST-free invoice with the correct wording, so you are not manually deleting tax lines or relabelling headings.

This is general information only and not tax advice; confirm your registration status and obligations with the ATO or a registered tax agent for your circumstances.