GST on consultant fees: general information for design practices

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This is general information, not tax or financial advice. It summarises public ATO guidance as we understood it on 27 October 2026. Your situation depends on your contracts and how you work. Check with a registered tax agent or the ATO.

Registering for GST

According to the ATO, a business must register for GST within 21 days of its GST turnover reaching A$75,000 or more, or of becoming likely to. Below that threshold registration is optional. GST is generally 10% of the price of a taxable sale.

This matters on a shared job because some consultants, often small specialists, may not be registered. A consultant who isn’t registered doesn’t charge GST on their fee.

Tax invoices

The ATO says a GST-registered business must provide a tax invoice within 28 days if a buyer asks for one for a taxable sale of more than A$82.50 including GST. A tax invoice must show, among other things:

• that it is intended to be a tax invoice
• the seller’s identity and ABN
• the date it was issued
• a brief description of what was sold, with quantity and price
• the GST amount (if any) payable, and the extent to which each item is taxable
• for sales of A$1,000 or more, the buyer’s identity or ABN

Who is the supplier?

There are two broad ways a consultant’s work reaches the client, and they lead to different GST outcomes:

On-charging versus reimbursement

The ATO’s ruling on reimbursements and agency (GSTR 2000/37) distinguishes between paying an expense as agent for someone else and incurring it as principal. Very broadly: where you pay a cost on behalf of a client as their agent, the reimbursement you receive is generally not payment for a supply by you; where you incur the cost yourself and pass it on, it is generally part of the price of your own taxable supply.

For a design practice, “on-charging” an engineer’s fee in your own invoice usually looks like the second case. Getting this wrong can mean GST is charged twice, or by the wrong party, so it is worth confirming with your accountant how your arrangements are set up.

Progressive or staged supplies

The ATO treats a supply made progressively or periodically, such as stages of design work paid as they are delivered, as a series of separate supplies, with each component attributed to the tax period in which it is paid or invoiced. In practice that means each stage invoice is its own tax event, which fits a staged schedule neatly.

Example: the same stage under both arrangements

How DrafterShare is planned to handle it

The planned default treats each consultant as supplying the client directly, with a tax invoice in the consultant’s own name, and supports consultants who aren’t registered for GST. Practices that subcontract can invoice the whole amount instead. See the FAQ, the split payments guide and the consultants page. DrafterShare is pre-launch; try the live demo.