GST Calculator
Total price (incl. GST)
$110.00
GST amount (10%)
$10.00
Adding 10% GST to $100.00 adds $10.00, for a total of $110.00 including GST.
Quick answer
GST in Australia is a flat 10% added to most goods and services. To add GST, multiply a GST-exclusive amount by 1.1. To remove GST, divide a GST-inclusive amount by 1.1 to get the ex-GST price, then subtract that from the total to find the GST component.
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Browse Tax & GSTHow it works
GST (Goods and Services Tax) is a flat 10% tax added to most goods and services sold or consumed in Australia. It’s a single national rate — there are no brackets, thresholds or state-by-state variations the way there are for income tax. A small number of items (like basic food, some health and medical services, and childcare) are GST-free, but everything else sold by a GST-registered business carries the same 10% rate.
There are two directions to the calculation, depending on whether your starting amount already includes GST:
Adding GST to a GST-exclusive amount — multiply by 1.1:
Total (incl. GST) = GST-exclusive amount × 1.1
GST amount = GST-exclusive amount × 0.1Removing GST from a GST-inclusive amount — divide by 1.1, not subtract 10%:
GST-exclusive amount = GST-inclusive amount ÷ 1.1
GST amount = GST-inclusive amount − GST-exclusive amountThat divide-by-1.1 step matters: subtracting a flat 10% from a GST-inclusive price overcorrects, because the original 10% was calculated on the smaller ex-GST amount, not the total. Dividing by 1.1 reverses the original multiplication exactly. A handy shortcut for the GST component alone is dividing the GST-inclusive amount straight by 11 — it produces the identical figure in one step, and is the method the ATO itself describes for working out the GST included in a sale price.
Worked example
Adding GST — a sole trader’s invoice. Marcus is a sole trader landscaper in Perth who quotes his labour at $250, GST-exclusive, for a day’s work. To invoice correctly, he needs to add 10% GST on top:
$250 × 1.1 = $275.00 total invoice, made up of the $250.00 fee plus $25.00 GST.
Removing GST — checking a receipt. Aisha, in Hobart, wants to know how much of a $110 GST-inclusive homewares receipt was actually tax. She divides by 1.1 to find the ex-GST price, then subtracts:
$110 ÷ 1.1 = $100.00 ex-GST, so the GST component was $110.00 − $100.00 = $10.00 (the same answer as $110 ÷ 11).
| Ex-GST amount | GST (10%) | Total (incl. GST) | |
|---|---|---|---|
| Marcus’s invoice (add GST) | $250.00 | $25.00 | $275.00 |
| Aisha’s receipt (remove GST) | $100.00 | $10.00 | $110.00 |
Frequently asked questions
Is GST always 10% in Australia?
Yes. GST has been a flat 10% since it was introduced on 1 July 2000, applied to most goods and services sold or consumed in Australia. Unlike income tax brackets or the Medicare levy, there's no tiered or income-based rate — it's a single flat percentage, and it hasn't changed since.
How do I work out the GST component of a total price?
If a price already includes GST, divide it by 1.1 to find the GST-exclusive amount, then subtract that from the total to get the GST component. A shortcut: dividing the GST-inclusive total straight by 11 gives you the same GST component directly, in one step.
What's the difference between a GST-inclusive and a GST-exclusive price?
A GST-exclusive price is the amount before the 10% GST is added — what a business actually earns from the sale. A GST-inclusive price is what the customer pays at the checkout, with GST already built in. Invoices and quotes often show both figures so the tax component is clear.
Why do you divide by 1.1 to remove GST instead of just subtracting 10%?
Subtracting 10% from a GST-inclusive price overcorrects, because that 10% was originally calculated on the smaller ex-GST amount, not the total. Dividing by 1.1 correctly reverses the multiplication used to add GST in the first place, so you get back the exact original ex-GST amount every time.
Are any goods or services GST-free in Australia?
Yes. Most basic food, many medical and health services, childcare, and some education courses are GST-free, meaning no GST is added to their price. Everything else — most retail goods, trades, professional services and hospitality — has GST charged at the standard 10% rate unless a specific exemption applies.
Do all businesses have to charge GST?
No. A business only needs to register for GST once its GST turnover reaches $75,000 a year ($150,000 for non-profits), though it can register voluntarily earlier. Below that threshold, registration is optional — once registered, GST must be charged on taxable sales and reported to the ATO on a Business Activity Statement.
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Written and verified by Nirbhay Tripathi
Last updated 18 August 2026
All rates on this page are verified againstATO — How Australian GST workson 18 August 2026. See our methodology for the full update calendar.