Skip to content
calcbloc
GST / 10% / AUSTRALIA

GST calculator

Add 10% GST to a price, or work out the GST included in a GST-inclusive price (one-eleventh of it), as the GST Act sets out.

Last verified: Methodology

Your details

01Amount

I want to

GST-inclusive price when removing GST; GST-exclusive price when adding it.

GST

$100.00

included in the price (1/11)

Price excluding GST
$1,000.00
Price including GST
$1,100.00
  • GST is 10% of the value of a taxable supply, and the value is the GST-inclusive price × 10/11 (GST Act ss 9-70, 9-75). So GST is one-eleventh of a GST-inclusive price.
  • GST-free supplies (Division 38: certain food, health and education) and input-taxed supplies (Division 40: such as residential rent) carry no GST. Amounts here are rounded to the cent.

GST: $100.00 included in the price (1/11)

Taking GST out
LineAmount
Price excluding GST$1,000.00
GST (10%)$100.00
Price including GST$1,100.00
GST-inclusive price
91%TAKE-HOME
  • Price excluding GST$1,00091%
  • GST$1009%

$100.00

included in the price (1/11)

How it's calculated

Australia's goods and services tax is 10% of the value of a taxable supply. The GST Act defines the value as the GST-inclusive price multiplied by 10/11, so the GST in a GST-inclusive price is one-eleventh of it.Federal Register of Legislation

  • Adding GST to a GST-exclusive price: multiply by 10% for the GST, or by 1.1 for the total.
  • Removing GST from a GST-inclusive price: divide by 11 for the GST, or multiply by 10/11 for the price before GST.

The formula

  • GST to add = price excluding GST × 10%
  • Price including GST = price excluding GST × 1.1
  • GST included = price including GST ÷ 11
  • Price excluding GST = price including GST × 10 ÷ 11

Worked example

The GST Act's own example is a car sold for $22,000: its value is $20,000 and the GST is $2,000. The calculator gives the same: $2,000.00 GST and $20,000.00 before GST.

$22,000 including GST (the GST Act example)GST / 10% / AUSTRALIA
LineAmount
Price excluding GST$20,000.00
GST (10%)$2,000.00
Price including GST$22,000.00

Adding GST to a $250 invoice gives $25.00 GST and a total of $275.00.

Assumptions and limitations

  • Taxable supplies only. GST-free supplies (Division 38 of the Act, such as certain food, health and education) and input-taxed supplies (Division 40, such as residential rent) have no GST.
  • Results are rounded to the cent. Special rules (margin scheme property sales, luxury cars, imports) are not covered.
FAQ

Questions people ask

How do I calculate GST in Australia?

GST is 10% of the price before GST. To add it, multiply the GST-exclusive price by 0.1 for the GST amount, or by 1.1 for the total. To find the GST already included in a price, divide the GST-inclusive price by 11. For example, $110 including GST contains $10 of GST, and the price before GST is $100.

Why is GST one-eleventh and not 10% of the total?

Because the 10% is charged on the price before GST, not on the total. If the price before GST is $100, GST adds $10 and the total is $110. The $10 is 10% of $100 but only one-eleventh of $110. The GST Act writes this as the value of the supply being the GST-inclusive price multiplied by 10/11.

What is the GST rate in 2026–27?

The rate is 10%, set by section 9-70 of the A New Tax System (Goods and Services Tax) Act 1999, and it is unchanged for 2026–27. The same section applies to every taxable supply, whether it is goods, services or property. The GST is worked out on the value of the supply, which is the GST-inclusive price multiplied by 10/11 under section 9-75.

Which items don't have GST?

GST-free supplies have no GST but the seller can still claim credits for GST in their costs. Division 38 of the GST Act covers them, including certain basic food, many health and medical services, and education courses. Input-taxed supplies, such as residential rent and many financial supplies, also have no GST, but the seller can't claim GST credits for related costs.

Do I need to register for GST?

Businesses must register for GST once their annual turnover reaches the registration turnover threshold set under the GST Act and its regulations, and some kinds of business must register whatever their turnover. Once registered you charge GST on taxable sales, issue tax invoices and claim GST credits on business purchases through your business activity statement. Check the current threshold and rules with the ATO.

Sources

  1. Federal Register of LegislationA New Tax System (Goods and Services Tax) Act 1999, sections 9-70 and 9-75 · retrieved 2026-10-17

Last verified: CalcBloc Editorial Team