How to add GST
Multiply the price by 10% and add it: A$1,000 plus A$100 GST is A$1,100. In one step: A$1,000 × 1.1 = A$1,100.
How to work out GST from a total
Divide the GST-inclusive total by 11 to get the GST: A$1,100 ÷ 11 = A$100. Divide the total by 1.1 to get the price without GST: A$1,000.
GST-free and input-taxed sales
Some sales are GST-free (no GST is charged, and you can still claim GST credits on what you buy for them) and some are input-taxed (no GST is charged and you generally cannot claim the credits). The ATO lists which sales fall into each group.
You must register for GST when your GST turnover reaches A$75,000, and within 21 days of reaching it. Below that you do not add GST to your invoices.
Rate and threshold from the Australian Taxation Office. Rate checked on 6 October 2026. Australian Taxation Office (ATO) · Australian Taxation Office (ATO)
QuickBilling adds GST per line on your invoices and keeps a GST summary for each period. See the tax summary.