Reverse GST Calculator for Australia
Enter a GST-inclusive price in dollars and get the amount excluding GST and the 10% GST it contains.
Result
Enter an amount to see the result.
For general information only, not tax advice. Some sales are GST-free or input-taxed – check with the ATO if you are unsure.
How to remove GST from a price
GST is 10% of the price before GST, which makes it exactly one-eleventh of a GST-inclusive price.
| Formula | Example: $110 | |
|---|---|---|
| Price excluding GST | total ÷ 1.1 | $110 ÷ 1.1 = $100.00 |
| GST | total ÷ 11 | $110 ÷ 11 = $10.00 |
| Check | excluding GST × 10% | $100 × 0.10 = $10.00 |
Taking 10% off the total is a common mistake: on $110 it gives a GST of $11 instead of $10.
Examples: GST inside common amounts
| Price including GST | Excluding GST | GST (1/11) |
|---|---|---|
| $50 | $45.45 | $4.55 |
| $100 | $90.91 | $9.09 |
| $110 | $100.00 | $10.00 |
| $500 | $454.55 | $45.45 |
| $1,100 | $1,000.00 | $100.00 |
Amounts are rounded to the nearest cent. The calculator works out the price excluding GST first and then subtracts it from the total, so the two always add back to the amount you entered. A receipt may show the GST rounded slightly differently.
GST rate in Australia
| Rate | Applies to |
|---|---|
| 10% | Most goods, services and other items sold or consumed in Australia |
| GST-free (0%) | Sales that are GST-free, such as most basic food |
Input-taxed sales also have no GST in the price, but they are treated differently from GST-free sales – the seller generally cannot claim GST credits for them.
Source: business.gov.au – Register for goods and services tax (GST).
Frequently asked questions
How do I work out GST from a GST-inclusive price?
Divide the price by 11. In a $110 price the GST is $110 ÷ 11 = $10, and the price excluding GST is $100. This works because GST is 10% of the GST-exclusive price, which makes it one-eleventh of the total.
How do I remove GST from a total?
Divide the total by 1.1. $110 ÷ 1.1 = $100 excluding GST. Then subtract to get the GST: $110 − $100 = $10.
Why can't I just take 10% off the total?
Because the 10% was added to the price before GST, not to the total. 10% off $110 is $99, but the correct GST-exclusive price is $100, so the GST is $10, not $11.
What does GST-free mean?
A GST-free sale has no GST in the price, so the amount excluding GST is the same as the total. Choose the GST-free option (0%) in the calculator for these items.
When does a business have to register for GST?
When its GST turnover is $75,000 or more, or $150,000 or more for a non-profit organisation.