GST Calculator
Add or remove 10% GST from any amount.
GST Calculator
Add or remove Australia's 10% GST from any amount, instantly.
Enter a GST-exclusive amount to find the GST and the GST-inclusive total.
Enter an amount to calculate GST.
How to Calculate GST in Australia
Australia's Goods and Services Tax (GST) is a flat 10% tax applied to most goods and services. Enter an amount above, choose whether you want to add GST to a price or remove GST from one, and the calculator does the rest — including a quick reference table for common amounts.
The Formulas
e.g. $100 × 1.10 = $110 (GST of $10)
e.g. $110 ÷ 1.10 = $100 (GST of $10)
Worked Example
Adding 10% GST to a $100 GST-exclusive price gives a GST-inclusive total of $110.00, with $10.00 being the GST component. Going the other way, removing GST from a $1,000 GST-inclusive price gives a GST-exclusive price of $909.09 and a GST amount of $90.91 — not $100, since the GST is calculated on the lower exclusive amount, not the inclusive total.
The Quick "Divide by 11" Trick
A fast mental-maths shortcut for finding the GST component of a GST-inclusive price: divide by 11, not 10. A $110 price divided by 11 is $10 — that's the GST. This works because a GST-inclusive price is made of 11 equal parts: 10 parts GST-exclusive price, 1 part GST.
Frequently Asked Questions
- How do I calculate GST in Australia?
- To add GST to a price, multiply the GST-exclusive amount by 0.10 to get the GST, then add it back on — $100 + 10% GST = $110. To remove GST from a price, divide the GST-inclusive amount by 1.1 — $110 ÷ 1.1 = $100 GST-exclusive, with $10 being the GST component. Use the "Add GST" or "Remove GST" toggle above to do either instantly.
- How much is GST in Australia?
- GST (Goods and Services Tax) in Australia is a flat 10%, applied to most goods and services sold or consumed in Australia. It's a national rate set by the Australian Government — not a state or territory rate — so it's the same whether you're in NSW, VIC, QLD, WA, SA, TAS, ACT or NT.
- What's the difference between GST-inclusive and GST-exclusive?
- A GST-exclusive amount is the price before GST is added — what a business actually earns from the sale. A GST-inclusive amount is the price a customer actually pays, with the 10% GST already built in. Advertised retail prices in Australia are legally required to be GST-inclusive.
- How do I work out the GST amount on a GST-inclusive price?
- Divide the GST-inclusive price by 11 — not by 10. For example, on a $110 GST-inclusive price, the GST component is $110 ÷ 11 = $10. This shortcut works because $110 is made up of 11 equal "tenths": 10 tenths is the GST-exclusive price and 1 tenth is the GST.
- Does GST differ by state, like NSW, VIC or QLD?
- No — GST is a federal tax and the 10% rate applies uniformly across every Australian state and territory. There's no separate "GST calculator NSW" rate; the calculation is identical no matter where in Australia the sale happens.
- How do I remove GST from a total to find the pre-GST price?
- Switch to "Remove GST" above and enter the GST-inclusive total. The calculator divides it by 1.1 (for the standard 10% rate) to give you the GST-exclusive price, and shows the GST amount separately — useful for reconciling a receipt, invoice or BAS.
- Is every purchase in Australia subject to GST?
- No. Most basic food, many medical and health services, and some education and childcare costs are GST-free, and some financial supplies are input-taxed. This calculator assumes the full amount is subject to standard-rate GST — for a GST-free or mixed transaction, apply the calculation only to the taxable portion.