GST on Invoices Checklist

Before you start

GST is the goods and services tax added to most taxable sales in Australia. Showing it correctly matters because a registered customer relies on your invoice to claim back the GST they paid, and because your own reporting depends on getting it right. This checklist is general guidance only, not tax advice — GST rules depend on your circumstances and change over time, so confirm the current detail at ato.gov.au or with your accountant.

The first thing to settle is whether GST applies to you at all. You generally charge GST only if you are registered for GST and making a taxable sale. If you are not registered, you do not add GST. For background, see when you need to charge GST.

Confirm GST applies

Before adding GST to anything, check:

• That you are registered for GST
• That the supply is a taxable sale, not GST-free or input-taxed
• Whether any part of the sale is treated differently
• How GST applies to overseas customers, which can differ
• That you would issue a tax invoice, not a plain invoice

If you are not registered you should not be charging GST, and adding it by mistake creates a problem for both you and the customer.

Show GST clearly on the invoice

When GST does apply, present it so the customer can read it at a glance:

1. Use the words 'tax invoice'
2. Show your ABN
3. Either state the GST amount, or note that the total includes GST
4. Make the GST-inclusive total unambiguous
5. Keep the GST line consistent with the line totals
6. Round and present figures consistently across the invoice

The customer's accounts team looks specifically for the GST treatment, so make it obvious rather than leaving them to work it out.

Handle mixed and adjusted supplies

Real invoices are not always all-taxable. Take care with:

• Mixed invoices — separate taxable and GST-free lines clearly
• Deposits — apply GST consistently between deposit and balance
• Discounts — confirm how GST sits with a discount applied
• Credit notes — reverse the GST as well as the net amount
• On-charged expenses — check the correct treatment of each

If you are ever unsure how GST applies to a particular supply, ask your accountant rather than guessing. For presentation detail, see how to show GST on an invoice.

Common mistakes

These GST slips show up most often:

• Charging GST while unregistered — adding GST you are not entitled to
• No 'tax invoice' or ABN — the customer cannot claim the credit
• Unclear mixed supplies — taxable and GST-free lines run together
• Hard-coded assumptions — relying on old advice instead of current rules

A consistent tax-invoice template prevents most of these. Our free invoice tools set out the standard GST fields. This remains general information only — confirm how GST applies to your situation with the ATO or your accountant before relying on it.