GST Calculator
Enter any amount to add or remove 10% GST instantly. Switch tabs to check whether your annual turnover crosses the GST registration threshold.
How GST works in Australia
Goods and Services Tax is 10% on most things. Add 10% to a GST-exclusive price, or divide a GST-inclusive total by 11 to find the GST component.
A $1,000 GST-exclusive sale becomes $1,100 inc-GST: $100 of that is GST.
A $1,100 GST-inclusive total contains $100 of GST and $1,000 of base price (inc/11 = GST).
Tax invoices over $82.50 (incl GST) must include the words "Tax Invoice", supplier ABN, date, item description, GST amount, and total. Sales over $1,000 (incl GST) must also show the buyer's identity or ABN.
When you must register for GST
If your annual GST turnover is $75,000 or more, you must register for GST and lodge a BAS. Non-profits get a $150,000 threshold.
Registration is mandatory once you cross the threshold. Late registration triggers backdated GST liability and penalties.
Voluntary registration below the threshold is allowed and sometimes useful: for B2B suppliers whose customers want a GST credit, or for businesses with significant input costs.