GST Calculator Australia

How the number is derived

Australian GST is a flat 10% on taxable supplies. Gross = net × 1.1, and the GST inside a gross figure is the gross divided by 11, a convenience that comes directly from the round rate.

Net = gross ÷ 1.1. The divide-by-eleven shortcut is exact rather than approximate, which makes mental reconciliation unusually easy compared with 19% or 21% systems.

An example

A net price of A$52.73 gives A$58.00 gross and A$5.27 of GST. Checking: 58 ÷ 11 = 5.27. ✓

For a registered business the A$5.27 is collected on behalf of the ATO and offset against GST paid on inputs. Buying the goods for A$23.73 plus A$2.37 of GST means A$2.90 remitted, 10% of the A$29 of value added.

GST-free supplies change the picture entirely: basic food, most health and education services, and exports carry no GST while still allowing full input credit, so a business selling them is typically in a permanent refund position.

The usual mistakes

GST-free and input-taxed are opposites in effect. GST-free allows input credits; input-taxed, financial supplies and residential rent, does not, making it materially worse for the supplier.

The food rules are famously fine-grained. Basic food is GST-free and prepared food is not, with the boundary producing genuine disputes over items that seem obviously one or the other.

What this changes

Confirm whether your supplies are taxable, GST-free or input-taxed before registering, because the three lead to very different positions. A GST-free business often benefits substantially from registering; an input-taxed one usually does not.

Then set the BAS reporting cycle deliberately. Monthly reporting suits a refund business and quarterly suits a payer, and the default is not always the better fit.

Registration, and the rules for offshore sellers

Registration is compulsory above A$75,000 of turnover, or A$150,000 for non-profits. Below that it is optional, and the same trade-off applies as elsewhere: input credit recovery against a 10% price disadvantage to consumers.

Offshore sellers face a separate regime. Since 2017 and 2018 respectively, overseas suppliers of digital products and of low-value imported goods must register and charge GST once they cross the A$75,000 threshold on sales to Australian consumers, with no physical presence required.

The threshold counts Australian consumer sales rather than total turnover, which businesses cross gradually and often without noticing. Monitoring turnover by destination country against each market's threshold is a small piece of reporting that prevents a retrospective liability on sales already made and margin already spent.

The taxable payments reporting and the requirement to hold a valid tax invoice for purchases above a modest threshold before claiming an input credit.

The threshold is low enough that most business purchases need one, and a supplier's ABN status is checkable against the public register, a supplier without a valid ABN triggers withholding obligations as well as blocking the credit.

Checking the ABN at the point of onboarding a new supplier is a two-minute step that prevents both problems.

Registration is the threshold that determines whether any of this applies. Businesses turning over less than the registration threshold need not register for GST and cannot claim input credits, and the calculation changes completely on either side of it. For overseas sellers shipping into Australia there is a separate low value imported goods regime with its own rules, which is where most confusion arises.