GST Calculator
Add 10% GST to a price, or take it out of a GST-inclusive price, and get the GST-exclusive, GST and GST-inclusive figures for an invoice or quote.
Result
Price including GST
$1,100.00
GST $100.00
- Price excluding GST
- $1,000.00
- GST (10%)
- $100.00
- Price including GST
- $1,100.00
GST is rounded to the nearest cent, with half a cent rounded up, as on a tax invoice for a single taxable sale.
Rates checked 12 October 2026 against the ATO · How we calculate · Calculated in your browser; nothing you enter is sent anywhere.
GST on common amounts
| Amount | GST to add | Price with GST | GST included in the amount |
|---|---|---|---|
| $100 | $10.00 | $110.00 | $9.09 |
| $250 | $25.00 | $275.00 | $22.73 |
| $500 | $50.00 | $550.00 | $45.45 |
| $1,000 | $100.00 | $1,100.00 | $90.91 |
| $2,500 | $250.00 | $2,750.00 | $227.27 |
| $5,000 | $500.00 | $5,500.00 | $454.55 |
Source: How GST works, ATO, last updated 14 September 2026.
When contractors must register for GST
You must register for GST if your GST turnover is $75,000 or more ($150,000 for non-profit organisations), or if you provide taxi or ride-sourcing travel, and you have 21 days to do it once you’re required to. You reach the threshold when your turnover for the current month and the previous 11 months is $75,000 or more, or when it is likely to be for the current month and the next 11 months. GST turnover is your total business income, not your profit, less the GST in your sales and a few other amounts. Below the threshold, registering is optional.
Once registered, you add GST to the price of your taxable sales, give tax invoices, claim GST credits on business purchases and report it on your activity statement. To see what GST means for your take-home pay, use the contractor pay calculator, which works from your rate excluding GST.
Source: Registering for GST, ATO, last updated 14 September 2026.
GST on tax invoices
- If a customer asks for a tax invoice, you must give one within 28 days, unless the sale is $82.50 or less including GST.
- The invoice must show the GST amount, or, if GST is exactly one-eleventh of the total, say “Total price includes GST”.
- Invoices for sales of $1,000 or more must also show the buyer’s identity or ABN.
Source: Tax invoices, ATO, last updated 18 September 2026.
Frequently asked questions
How do I work out the GST in a price?
Divide the GST-inclusive price by 11. A $1,100.00 price includes $100.00 of GST, and $1,000.00 before GST. Dividing by 10 instead gives the wrong answer, because GST is 10% of the price before GST, not of the total.
How do I add GST to a price?
Multiply the price excluding GST by 1.1, or add 10% of it. $250.00 plus GST is $275.00.
How is GST rounded?
When there is one taxable sale on a tax invoice, GST is rounded to the nearest cent, with half a cent rounded up. For a $10.00 price, GST is $0.91. Invoices with several taxable sales have their own rounding rules (ATO).