Australian GST Calculator
Add or remove 10% Australian GST instantly. GST-inclusive, exclusive and component amounts for invoices, quotes and BAS. ATO-aligned format for 2026-27.
Enter the price before GST; the calculator adds the 10% GST component.
Enter an amount to calculate GST
Australia's GST rate is 10%. The calculation depends on whether your starting price includes GST or not:
The "divide by 11" formula works because GST-inclusive prices contain the original amount plus 10%. Mathematically: price ÷ 1.1 gives the GST-exclusive amount, and price ÷ 11 gives the GST component.
You generally must register for GST and charge it on taxable sales if your business has a GST turnover of $75,000 or more per year ($150,000 for non-profit organisations). Taxi, limousine and ride-sourcing providers must register regardless of turnover; you must also register if you want to claim fuel tax credits.
If you are close to that line, use the dedicated $75,000 GST registration threshold guide to decide whether you are in optional, watch-list, or must-register territory.
Once registered, you charge 10% GST on most goods and services you sell, and you can claim GST credits on your business purchases. Registered businesses report and pay GST through the BAS — see BAS and PAYG due dates for the lodgment calendar, or the sole trader tax action plan for a broader quarterly checklist.
GST on common amounts
Two directions come up constantly: adding 10% GST to a GST-exclusive price, and pulling the GST component out of a GST-inclusive total using the 1/11 rule. Both are shown below for common invoice and quote amounts.
Adding GST (GST-exclusive → GST-inclusive)
| Amount (excl. GST) | GST (10%) | Total (incl. GST) |
|---|---|---|
| $10 | $1.00 | $11.00 |
| $50 | $5.00 | $55.00 |
| $100 | $10.00 | $110.00 |
| $500 | $50.00 | $550.00 |
| $1,000 | $100.00 | $1,100.00 |
| $5,000 | $500.00 | $5,500.00 |
| $10,000 | $1,000.00 | $11,000.00 |
GST component = amount × 10%. Total = amount + GST component.
Removing GST (GST-inclusive → GST-exclusive, the 1/11 rule)
| Amount (incl. GST) | GST component (÷11) | Amount (excl. GST) |
|---|---|---|
| $10 | $0.91 | $9.09 |
| $50 | $4.55 | $45.45 |
| $100 | $9.09 | $90.91 |
| $500 | $45.45 | $454.55 |
| $1,000 | $90.91 | $909.09 |
| $5,000 | $454.55 | $4,545.45 |
| $10,000 | $909.09 | $9,090.91 |
GST component = amount ÷ 11. GST-exclusive amount = total − GST component.
Calculator amounts are rounded to the nearest cent. For invoices containing multiple taxable lines, use the GST amount shown on the invoice or your accounting system's consistent invoice-rounding method.
Three worked GST examples
(a) Adding 10% GST to a quoted price
A tradesperson quotes a job at $8,000 GST-exclusive.
GST = $8,000 × 10% = $800.00
Total quoted price = $8,000 + $800.00 = $8,800.00
(b) Extracting GST from a GST-inclusive total (the 1/11 rule)
A retail price tag shows $220, GST-inclusive.
GST component = $220 ÷ 11 = $20.00
GST-exclusive amount = $220 − $20.00 = $200.00
(c) A small-business invoice and what goes on the BAS
A GST-registered sole trader invoices a client $1,650, GST-inclusive, for a consulting job.
GST on the sale = $1,650 ÷ 11 = $150.00
Net sale (ex GST) = $1,650 − $150.00 = $1,500.00
On the BAS, the full $1,650 is included in G1 (total sales), and the $150.00 GST component is reported at 1A (GST on sales). It's payable at the next BAS due date — see BAS and PAYG due dates.
What is GST-free vs input-taxed?
Not every sale attracts the standard 10% GST. Two categories sit outside the normal calculation, and they work differently:
The distinction matters for businesses: selling GST-free goods still lets you claim input tax credits on your costs, while selling input-taxed supplies does not. This calculator assumes a standard 10%-rated supply — check with the ATO or a tax agent if your sale might be GST-free or input-taxed.
Is GST always 10% in Australia?
What is the 1/11 rule for GST?
Is GST 10% or 15% in Australia?
How do I calculate GST on an invoice?
What is a GST-inclusive price?
Who has to register for GST?
When do I report and pay GST?
Does GST apply to imports and low-value goods bought online?
Tax Accuracy & Sources
Calculates one standard-rated taxable supply at the 10% rate and rounds the displayed result to cents. It does not cover mixed supplies, GST-free or input-taxed supplies, margin schemes, adjustments, credit notes, registration decisions, or multi-line invoice rounding.