GST calculator
Type an amount and choose whether it already includes GST.
GST in common amounts
| Price incl. GST | GST | Price excl. GST |
|---|---|---|
| $11.00 | $1.00 | $10.00 |
| $55.00 | $5.00 | $50.00 |
| $110.00 | $10.00 | $100.00 |
| $220.00 | $20.00 | $200.00 |
| $550.00 | $50.00 | $500.00 |
| $1,100.00 | $100.00 | $1,000.00 |
| $2,200.00 | $200.00 | $2,000.00 |
| $5,500.00 | $500.00 | $5,000.00 |
| $11,000.00 | $1,000.00 | $10,000.00 |
The two formulas
Adding GST: price × 1.1 = price including GST.
Finding GST in a total: total ÷ 11 = GST; total − GST = price before GST.
Some things are GST-free: most basic food, many health and education services, and exports. This calculator assumes the standard 10% rate applies.
Questions
How do I work out GST from a total?
Divide the GST-inclusive price by 11. For example, $220 ÷ 11 = $20 of GST, so the price before GST is $200.
How do I add GST to a price?
Multiply the price by 1.1. $500 × 1.1 = $550, of which $50 is GST.
Why is it divide by 11 and not 10%?
GST is 10% of the price before GST. In a GST-inclusive price the GST is one part in eleven (10 ÷ 110), so taking 10% off the total would understate the pre-GST price.
When do I have to register for GST?
Businesses must register once their GST turnover is $75,000 or more ($150,000 for non-profits). Taxi and ride-sourcing drivers must register regardless of turnover.
Sources
Checked 26 September 2026. OneCalcs is independent and not affiliated with the ATO or Fair Work.