How do I charge GST on an invoice?

GST is 10%. If your prices are GST-exclusive, GST is the subtotal multiplied by 0.1 and the total is the subtotal multiplied by 1.1. If your prices already include GST, the GST inside the total is the total divided by 11 — not 10% off the total.

Why divide by 11 and not take 10% off?

Because the GST was calculated on the pre-GST amount, not on the total. On a $1,320 GST-inclusive total, the GST is $120 — ten percent of the $1,200 underneath. Taking 10% off $1,320 would give $132, which overstates the GST.

What if only some items on my invoice have GST?

Do not use the blanket "total price includes GST" statement, because it would be untrue. Mark each line as taxable or GST-free, subtotal the two groups separately, and show the GST calculated on the taxable group only.

Do I put the customer's ABN on the invoice?

It is required once the invoice is $1,000 or more including GST — either the buyer's identity or their ABN. Below that it is optional, but including it on every invoice is simpler than remembering the threshold.

Invoicing5 min read

How to charge GST on an invoice in Australia

This is the same invoice written out in full, with the numbers done. If you are not sure how to charge GST on an invoice, where the GST line goes, or what to do when half the invoice is GST-free, this is the walkthrough.

Last updated 6 September 2026

Header: say what the document is

The words "Tax invoice" go at the top. This is a requirement, not a convention — the document has to be identifiable as intended to be a tax invoice.

Only use those words if you are registered for GST. If you are not, the heading is "Invoice" and there is no GST anywhere on the page.

Who is billing, and who is being billed

Your business name and your ABN are both required. The ABN is the field most often missing from a template downloaded from an overseas site, and its absence can mean a business customer has to withhold tax from your payment.

The customer's name or ABN is required once the invoice reaches $1,000 including GST. Put it on every invoice anyway — it removes a threshold you would otherwise have to remember mid-invoice.

The line items

Each line needs a brief description, the quantity and the price. "Consulting" on its own is thin; "Consulting — site audit, 6 hours" is a description.

Decide once whether your unit prices are shown GST-exclusive or GST-inclusive, and label the column accordingly. Mixing the two within one invoice is how the total ends up wrong.

A worked example

Three lines, GST-exclusive pricing, all taxable. GST is 10%, so the GST is a tenth of the subtotal and the total is the subtotal times 1.1.

Description	Qty	Unit price (ex GST)	Amount (ex GST)
Site audit — consulting	6 hrs	$120.00	$720.00
Written report	1	$300.00	$300.00
Travel — regional site visit	1	$180.00	$180.00
Subtotal (ex GST)			$1,200.00
GST (10%)			$120.00
Total (inc GST)			$1,320.00

The other direction: GST inside a total

If you price GST-inclusive — common in retail and hospitality — you already know the total and need to show the GST inside it. Divide the total by 11.

The divide-by-11 rule catches people out because the instinct is to take 10% off. Taking 10% off $1,320 gives $132, which is wrong. $1,320 ÷ 11 = $120, which is right, because the $120 of GST was calculated on the $1,200 beneath it, not on the total.

$1,320 inc GST → GST is $1,320 ÷ 11 = $120
$1,320 inc GST → pre-GST amount is $1,320 ÷ 1.1 = $1,200
Where every line is taxable, you may state "Total price includes GST" instead of showing the amount separately.

When only some lines carry GST

Some sales are GST-free — most basic food, and certain health and education supplies among others. If an invoice mixes taxable and GST-free lines, you cannot use the blanket "total price includes GST" statement, because it would not be true.

Show it per line instead. Mark each line as taxable or GST-free, subtotal the two groups separately, and show the GST as a single figure calculated on the taxable group only. The requirement is that the invoice shows the extent to which each sale includes GST, and a per-line marker is the clearest way to satisfy it.

Description	Amount	GST status
Catering — hot food service	$400.00	Taxable
Bread and milk supplied	$100.00	GST-free
Subtotal	$500.00
GST (on $400 taxable only)	$40.00
Total	$540.00

The footer: how you get paid

None of this is required by the ATO, and all of it decides how fast the invoice clears.

A real due date as a date, not "net 14".
Account name, BSB and account number. All three — a transfer without an account name generates a phone call.
A reference to quote, usually the invoice number, so the payment can be matched.
The PO or job number if the customer issued one. Without it, the invoice waits.

Or let Invoices do it

Rather than rebuild this each time, Regentflow's invoice builder does the GST arithmetic and the numbering, and gives you a PDF at the end.

About Invoices See pricing

Questions

How do I charge GST on an invoice?: GST is 10%. If your prices are GST-exclusive, GST is the subtotal multiplied by 0.1 and the total is the subtotal multiplied by 1.1. If your prices already include GST, the GST inside the total is the total divided by 11 — not 10% off the total.
Why divide by 11 and not take 10% off?: Because the GST was calculated on the pre-GST amount, not on the total. On a $1,320 GST-inclusive total, the GST is $120 — ten percent of the $1,200 underneath. Taking 10% off $1,320 would give $132, which overstates the GST.
What if only some items on my invoice have GST?: Do not use the blanket "total price includes GST" statement, because it would be untrue. Mark each line as taxable or GST-free, subtotal the two groups separately, and show the GST calculated on the taxable group only.
Do I put the customer's ABN on the invoice?: It is required once the invoice is $1,000 or more including GST — either the buyer's identity or their ABN. Below that it is optional, but including it on every invoice is simpler than remembering the threshold.