Australia GST Calculator
Quickly calculate Australian Goods and Services Tax to add 10% to net prices or remove the 1/11th GST component from gross prices with exact ATO rounding.
Interactive GST Calculator
Calculation Results
Net Amount (Excl. GST)
$100.00
GST Amount (10%)
$10.00
Gross Total (Incl. GST)
$110.00
Formula applied: $100.00 × 10% = $10.00 tax; total = $110.00
How GST is Calculated
1. Adding GST (Net to Gross)
To calculate the gross price when starting with a net (exclusive) price:
Gross Amount = Net Amount + GST Amount
Example: On a $100 net item, GST is $100 × 10% = $10.00. Total gross is $110.00.
2. Removing GST (Gross to Net)
To extract the tax from an inclusive gross price:
Net Amount = Gross Price − GST Amount
Section 9-75 of the GST Act defines GST payable as exactly 1/11th of the price.
Common GST Calculations Table
Quick reference matrix showing standard calculations for common amounts, precomputed with exact rounding.
Adding 10% GST (Net → Gross)
| Net Price | GST (10%) | Gross Total |
|---|---|---|
| $10.00 | +$1.00 | $11.00 |
| $25.00 | +$2.50 | $27.50 |
| $50.00 | +$5.00 | $55.00 |
| $100.00 | +$10.00 | $110.00 |
| $110.00 | +$11.00 | $121.00 |
| $250.00 | +$25.00 | $275.00 |
| $500.00 | +$50.00 | $550.00 |
| $1,000.00 | +$100.00 | $1,100.00 |
| $5,000.00 | +$500.00 | $5,500.00 |
Removing GST (Gross → Net)
| Gross Total | GST Content | Net Price |
|---|---|---|
| $10.00 | -$0.91 | $9.09 |
| $25.00 | -$2.27 | $22.73 |
| $50.00 | -$4.55 | $45.45 |
| $100.00 | -$9.09 | $90.91 |
| $110.00 | -$10.00 | $100.00 |
| $250.00 | -$22.73 | $227.27 |
| $500.00 | -$45.45 | $454.55 |
| $1,000.00 | -$90.91 | $909.09 |
| $5,000.00 | -$454.55 | $4,545.45 |
Statutory Rounding Rules
Under Australian Taxation Office ruling GSTR 2000/10, where the calculation of GST results in a fraction of a cent, the amount is rounded to the nearest whole cent. An exact half-cent (0.5 cents) is rounded up to the whole cent.
Official Regulatory Authorities & Legislation
Calculation rules verified against published statutory sources on 19 October 2026.
- A New Tax System (Goods and Services Tax) Act 1999 (Cth)
Section 9-70: GST rate of 10%; Section 9-75: GST payable is 1/11th of the price.
- ATO Goods and Services Tax Ruling GSTR 2000/10
ATO statutory rules on rounding GST amounts to the nearest whole cent (half-cent rounded up).
- Australian Taxation Office: GST-free sales
Rules distinguishing taxable supplies from GST-free items and input taxed sales.
Looking for Australian income tax estimates?
Estimate your 2026–27 individual income tax, Low Income Tax Offset (LITO), and Medicare levy with official ATO brackets.
Frequently Asked Questions
How is Australian GST calculated?
Australian GST is a flat 10%. To add GST to a net amount, multiply the net price by 0.10. To remove GST from a GST-inclusive price, divide the price by 11 (the statutory 1/11th rule under section 9-75 of the GST Act).
Why is GST 1/11th of the price rather than 10%?
When a price already includes 10% GST, the total price represents 110% of the original value. The tax portion is 10 / 110 = 1/11. For example, in a $110 inclusive price, the GST is exactly $110 / 11 = $10, leaving a net price of $100.
How does rounding work for Australian GST?
Under ATO ruling GSTR 2000/10, GST is rounded to the nearest cent. If the remaining fraction is exactly half a cent ($0.005), it is rounded up to the nearest whole cent.
Which items are GST-free in Australia?
Most basic food products, some medical and health services, certain medicines, educational courses, and exports are GST-free. Input taxed sales (such as residential rent and financial services) also do not include GST in the price.
Related calculators & tax tools
- United Kingdom
UK VAT Calculator 2026–27: Add or Remove VAT
Calculate UK VAT at standard 20%, reduced 5%, or 0% rates. Add VAT to net prices or remove VAT from gross totals with exact penny rounding.
Open - Australia
Australia income tax calculator 2026–27
Estimate annual income tax and Medicare levy for a single Australian resident, with a line-by-line breakdown.
Open - United Kingdom
UK take-home pay calculator 2026–27
Estimate take-home pay in England, Wales or Northern Ireland: Income Tax, National Insurance, a student loan and a pension, with the working shown.
Open - United Kingdom
£50,270 Salary After Tax UK 2026–27
Take-home pay estimate on a £50,270 annual salary for 2026–27: £39,714.64 net pay (£3,309.55 per month) with £7,540 Income Tax and £3,015.36 National Insurance.
Open