Tax
GST Calculator
Add 10% GST to a price or work out the GST and the ex-GST amount inside a GST-inclusive price, to the cent.
Result
Updates as you typePrice including GST
$1,100.00
- GST (10%)
- $100.00
- Price excluding GST
- $1,000.00
How it's calculated
GST is charged at 10% on the ex-GST price of a taxable sale. Working back from a GST-inclusive price, the GST is one eleventh of the total, because 110% ÷ 11 = 10%.
A common mistake is to take 10% of the inclusive price; that overstates the GST. Amounts are rounded to the cent and the ex-GST amount plus GST always equals the total.
Worked example
$2,500.00 at 10% GST:
- If $2,500.00 excludes GST: GST = $2,500.00 × 10% = $250.00 → $2,750.00 including GST
- If $2,500.00 includes GST: GST = $2,500.00 / 11 = $227.27 → $2,272.73 excluding GST
GST table
GST on common amounts
| Amount | If ex-GST: total incl. GST | If incl. GST: GST inside | If incl. GST: ex-GST |
|---|---|---|---|
| Amount: $50.00 | If ex-GST: total incl. GST$55.00 | If incl. GST: GST inside$4.55 | If incl. GST: ex-GST$45.45 |
| Amount: $100.00 | If ex-GST: total incl. GST$110.00 | If incl. GST: GST inside$9.09 | If incl. GST: ex-GST$90.91 |
| Amount: $500.00 | If ex-GST: total incl. GST$550.00 | If incl. GST: GST inside$45.45 | If incl. GST: ex-GST$454.55 |
| Amount: $1,000.00 | If ex-GST: total incl. GST$1,100.00 | If incl. GST: GST inside$90.91 | If incl. GST: ex-GST$909.09 |
| Amount: $5,000.00 | If ex-GST: total incl. GST$5,500.00 | If incl. GST: GST inside$454.55 | If incl. GST: ex-GST$4,545.45 |
| Amount: $10,000.00 | If ex-GST: total incl. GST$11,000.00 | If incl. GST: GST inside$909.09 | If incl. GST: ex-GST$9,090.91 |
Frequently asked questions
How do I add GST to a price?
Multiply the ex-GST price by 10% to get the GST, then add it: $1,000.00 ex-GST attracts $100.00 GST, so the GST-inclusive price is $1,100.00. Equivalently, multiply the ex-GST price by 1.1.
How do I work out the GST in a GST-inclusive price?
Divide the GST-inclusive price by 11. $1,000.00 including GST contains $90.91 GST and $909.09 ex-GST. Taking 10% of the inclusive price gives the wrong answer.
What is the GST rate in Australia?
GST is a broad-based tax of 10% on most goods, services and other items sold or consumed in Australia, under A New Tax System (Goods and Services Tax) Act 1999. The rate has been 10% since GST began on 1 July 2000.
Which sales are GST-free or input-taxed?
Some sales carry no GST: GST-free sales (for example most basic food, many health and education services and exports) and input-taxed sales (for example residential rent and most financial supplies). This calculator assumes a taxable sale; check the ATO's lists if you are not sure.
Does the calculator handle rounding like a tax invoice?
Amounts are rounded to the cent and the ex-GST amount plus the GST always equals the GST-inclusive total. On invoices with many lines, the ATO allows rounding per line or on the total; totals can differ by a cent between the two methods.
Sources
Assumes a taxable sale at the standard rate; GST-free and input-taxed sales are not covered. Results are for guidance only.
GST 10% · Updated: