GST calculator
Add or remove 10% Australian GST from any amount. Instant, free and nothing to sign up for.
GST rate: 10% (Australia)
Excluding GST
$1,000.00
GST (10%)
$100.00
Including GST
$1,100.00
$1,000.00 × 10% = $100.00 GST
How to calculate GST
Australia’s Goods and Services Tax (GST) is 10% on most goods and services. Here are the only formulas you need:
Add GST
Price × 1.1
GST = price × 0.1
Remove GST
Price ÷ 1.1
GST = price ÷ 11
Worked examples
| Calculation | Excl. GST | GST | Incl. GST |
|---|---|---|---|
| Add GST to $100.00 | $100.00 | $10.00 | $110.00 |
| Add GST to $1,000.00 | $1,000.00 | $100.00 | $1,100.00 |
| Remove GST from $110.00 | $100.00 | $10.00 | $110.00 |
| Remove GST from $550.00 | $500.00 | $50.00 | $550.00 |
| Add GST to $2,499.99 | $2,499.99 | $250.00 | $2,749.99 |
Why do you divide by 11?
GST is 10% of the price before tax. Once it’s added, the total is 110% of the original — so GST makes up 10 of every 110 dollars, or one-eleventh of the total. That’s why taking 10% off a GST-inclusive price gives the wrong answer: 10% of $110 is $11, but the GST in $110 is $10.
When do you need to charge GST?
Only if you’re registered for GST. According to the ATO, you must register once your GST turnover reaches $75,000 (or $150,000 for non-profits), and you then have 21 days to do it. Some sales are GST-free, like most basic food. Not sure where you stand? Read Do I need to charge GST?
Frequently asked questions
How do I calculate GST in Australia?
GST is 10%. To add GST to a price, multiply it by 1.1 (or multiply by 0.1 to get just the GST). To find the GST in a price that already includes GST, divide it by 11.
How do I remove GST from a price?
Divide the GST-inclusive price by 1.1 to get the amount excluding GST. The GST component is the inclusive price divided by 11. For example, $110 includes $10 GST, so the price excluding GST is $100.
Why is GST one-eleventh and not 10% of the total?
GST is 10% of the price before GST. Once it's added, the total is 110% of the original price — so the GST makes up 10/110, or one-eleventh, of the total.
Do I have to charge GST?
Only if you're registered for GST. You must register once your GST turnover reaches $75,000 or more (or $150,000 for non-profits), and taxi and ride-sourcing drivers must register regardless of turnover. Some sales, such as most basic food, are GST-free.
Is this GST calculator free?
Yes. It's free to use, with no sign-up. The calculation runs in your browser and nothing you type is stored.
General information only, not tax advice. Results are rounded to the nearest cent. Check ato.gov.au or a registered tax agent for your situation.
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