A GST calculator that shows the working.
$200.00 plus $20.00 GST is $220.00
This number is an example. Type over it.
The working
- GST is 10% of the price, so multiply by 0.1$200.00 × 0.1= $20.00
- Add the GST to the price$200.00 + $20.00= $220.00
$200.00 plus $20.00 GST is $220.00
Type a price and the GST appears with every step of the working, so you can check it by hand. It uses Australia’s 10% GST and happens in your browser; nothing you type is sent anywhere.
How do you add GST to a price?
Multiply the price by 0.1 and add the result, because GST is 10% of the price before GST (section 9-70 of the GST Act). For $200: 200 × 0.1 = 20, then 200 + 20 = 220. Multiplying by 1.1 gets there in one sum: 200 × 1.1 = 220.
How do you take GST out of a price?
Divide the GST-inclusive price by 11 to find the GST, then take it off. For $220: 220 ÷ 11 = 20, then 220 − 20 = 200.
The 11 comes from the 10%. Ten parts of price gain one part of GST, making eleven, and the GST is one of the eleven. Taking 10% off a GST-inclusive price is a common mistake: 10% of $220 is $22, not the $20 of GST in it.
How much is GST on common prices?
The same price gives different GST depending on whether it is the price before GST or the price including it.
| Price | Adding GST: GST and total | Taking GST out: GST and price before |
|---|---|---|
| $10.00 | $1.00, total $11.00 | $0.91, before GST $9.09 |
| $50.00 | $5.00, total $55.00 | $4.55, before GST $45.45 |
| $100.00 | $10.00, total $110.00 | $9.09, before GST $90.91 |
| $250.00 | $25.00, total $275.00 | $22.73, before GST $227.27 |
| $1,000.00 | $100.00, total $1,100.00 | $90.91, before GST $909.09 |
How is GST rounded to the cent?
When the GST doesn’t come out to a whole number of cents, this calculator rounds it to the nearest cent, with half a cent going up, and marks that step with ≈. It then works out the other figure from the rounded GST, so for a price in whole cents the price before GST and the GST add up to the total. For $100 including GST: 100 ÷ 11 ≈ 9.09, then 100 − 9.09 = 90.91. Rounding half a cent up is the rule section 9-90 of the GST Act sets for an invoice with one taxable sale.
This page assumes the whole price is taxable. For GST-free items and the ATO’s rounding rules on invoices, see how to add or remove 10% GST on a calculator.