GST on construction supplier invoices: what to check

By CostCode. Last reviewed 24 Sep 2026 against the official sources below, including the ATO's guidance.

Most of what a construction business buys carries GST at ten per cent, and a GST-registered buyer can usually claim it back. That makes the GST line easy to wave through. It is also where small mistakes sit unnoticed.

In short

Only a business registered for GST should charge it, and a business has to register once its GST turnover reaches $75,000.(ATO: Registering for GST)
To claim the GST credit on a purchase over $82.50 including GST you need a valid tax invoice, and the ATO says to wait for it.(ATO: When you can claim a GST credit)
The slips to look for: GST over ten per cent of the price it's charged on, GST on a line agreed GST-free, GST with no ABN printed, and lines plus GST that come to a different total.

Who can charge GST

Only a business registered for GST should charge it. A business has to register once its GST turnover reaches $75,000, and one below that can choose to register. So a small subcontractor may quite properly send an invoice with no GST on it.(ATO: Registering for GST)

To see whether a supplier is registered, search their ABN on ABN Lookup.(ABR: ABN Lookup)

Claiming it back

To claim a GST credit on a purchase over $82.50 including GST you need a valid tax invoice. If you don't have it yet, the ATO's advice is to wait for it before claiming, even if the credit then lands in a later period.(ATO: When you can claim a GST credit)

A tax invoice can show the GST as an amount or, where the GST is exactly one eleventh of the total, with a statement such as "Total price includes GST".(ATO: Tax invoices)

The slips worth checking for

None of these needs a tax adviser to spot. Each is a comparison of numbers already on the page:

GST worked out on the wrong base, so it comes to more than ten per cent of the price it is charged on.
GST charged on a line you agreed with the supplier would be GST-free.
GST charged with no ABN printed on the invoice.
The lines plus GST coming to a different figure from the total at the bottom.

Contractor payments and TPAR

Separately from GST, a business mainly in building and construction generally reports its payments to contractors for building and construction services each year in a taxable payments annual report, due by 28 August.(ATO: Building and construction services (TPAR); ATO: Taxable payments annual report (TPAR))

Where CostCode fits

The free invoice check tests one invoice for GST over ten per cent, GST with no ABN printed, and whether the lines and GST reconcile to the total. In an account, CostCode also checks GST on lines your agreed schedule says are GST-free. It won't tell you whether GST should apply to a particular supply; that is a question for the ATO or your adviser.

Questions

Should a supplier who isn't registered for GST charge GST?

No. Only GST-registered businesses charge GST. ABN Lookup shows whether a supplier's ABN is registered.(ABR: ABN Lookup; ATO: Registering for GST)

At what turnover does a business have to register for GST?

When its GST turnover is $75,000 or more. Below that, registering is optional.(ATO: Registering for GST)

Can I claim the GST before the tax invoice arrives?

For purchases over $82.50 including GST you need the tax invoice first; the ATO says to wait for it, even if that means claiming in a later period.(ATO: When you can claim a GST credit)

Sources

General information, not tax, legal or financial advice. The rules have exceptions and change over time: the official pages above are the authority, and your accountant or the ATO can tell you how they apply to your business.