Australian GST Calculator

GST calculator: frequently asked questions

• How do I calculate GST from a total using this calculator?
  Switch to "Remove GST (Inclusive)" mode above and enter the total. For example, on a $770 total, $770 ÷ 11 = $70 GST, which leaves $700 as the GST-exclusive price.
• How do I add GST to a price?
  Multiply the GST-exclusive price by 1.1 (or add 10% of the price to itself). For example, $340 × 1.1 = $374, meaning $34 of that total is GST.
• How do I remove GST from a price (excluding GST calculator)?
  Divide the GST-inclusive total by 11 to find the GST component, then subtract it from the total to get the price excluding GST. For a $770 total: $770 ÷ 11 = $70 GST, so the GST-exclusive price is $700.
• Is dividing by 1.1 the same as dividing by 11?
  No. Mixing them up is one of the most common GST mistakes. ÷ 1.1 gives you the GST-exclusive price; ÷ 11 gives you just the GST component. "Remove GST" mode above works out both at once.
• What GST rate does this calculator use?
  10% by default, which is Australia's standard rate since GST began in July 2000, but you can change the GST Rate field above if you ever need a different percentage.
• Is this the same method the ATO uses to calculate GST?
  Yes. The ATO calculates GST payable using the same 1/11th rule: divide the GST-inclusive amount by 11. This calculator uses that exact formula, so the result matches what you'd report on a BAS.
• Does this calculator work for GST-free items?
  No. It assumes the amount is subject to GST. Some purchases in Australia are GST-free, including most fresh food and basic groceries, health and medical services, education courses, and some childcare.