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Invoicing

GST-inclusive workshop invoices in Australia

Why workshop prices are usually entered including GST, and how to keep the invoice maths clear.

Published 12 July 2026 | 7 minute read

Start with the price the customer was told

Australian retail customers expect the quoted price to include GST. If a service advisor says brake pads are $220, the invoice should not add another $22 at the end. The $220 is the GST-inclusive amount unless the business has clearly stated otherwise.

Calculate the GST component from the inclusive total

For a line taxed at 10%, the GST component of a GST-inclusive amount is one-eleventh of that amount. A $220 line contains $20 GST and has an ex-GST value of $200. Multiplying $220 by 10% and adding it again would produce the wrong total.

Keep tax decisions on each line

Labour, parts and other charges may not always use the same tax treatment. Store the GST rate against each line and calculate document totals from the lines. That keeps quotes, purchase orders and invoices consistent when a description or quantity changes.

What MechAxis changes

MechAxis treats entered unit prices as GST inclusive. Each applicable quote, purchase order and invoice line carries its GST rate. The document shows the inclusive total, the GST component and the ex-GST amount without asking staff to reverse-calculate them.

Common questions

How much GST is included in $110?

$10. Divide a GST-inclusive amount taxed at 10% by 11 to find the GST component.

Should a workshop quote show GST?

A customer quote should make the total payable clear and identify the GST component where required. Business circumstances vary, so workshops should confirm document requirements with their accountant.