GST Calculator Australia
Add 10% GST to a price or strip GST out of a tax-inclusive total. The calculator shows the GST amount, the exclusive price and the inclusive price side by side.
- ATO-based tax rates
- Instant results
- No sign-up
- Private by design
Your amount
Enter a price, invoice total or quote.
All calculations run locally in your browser.
GST component
Removed from a $1,100.00 inclusive total
- GST-exclusive
- $1,000.00
- GST-inclusive
- $1,100.00
- GST as % of total
- GST fraction
- 1/11
Invoice split
- Amount before GST
- $1,000.00
- GST at 10%
- +$100.00
- Total including GST
- $1,100.00
The formula used
$1,100.00 ÷ 1.1 = $1,000.00 before GST
Rounding can shift the last cent on an invoice. Most accounting software rounds the GST component to two decimal places.
Adding GST and removing GST
Adding GST and removing GST are not the same operation in reverse, because the starting point is different. If you know the price before tax, adding 10% is straightforward. If you know the total after tax, you cannot simply subtract 10% from that total; the GST is only 1/11 of the inclusive figure.
Add GST: exclusive price × 1.10. Remove GST: inclusive price ÷ 1.10. The GST itself is the inclusive price ÷ 11.
A $1,000 job plus GST is $1,100. But 10% of $1,100 is $110, so subtracting it gives $990, which is $10 too low. Dividing $1,100 by 1.1 gives the correct $1,000 exclusive price and a $100 GST component. That difference matters on quotes, invoices and BAS calculations.
The GST formulas
The calculator uses three simple relationships. Use them to check an invoice or to build a spreadsheet of your own.
- GST-exclusive to inclusive: multiply by (1 + rate ÷ 100). At 10%, multiply by 1.1.
- GST-inclusive to exclusive: divide by (1 + rate ÷ 100). At 10%, divide by 1.1.
- GST component: inclusive amount − exclusive amount, or inclusive amount × rate ÷ (100 + rate). At 10%, that is inclusive ÷ 11.
If you are preparing a tax invoice, show the GST amount separately and make sure the total matches the sum of the exclusive price and the GST. A tax invoice must include the seller’s identity and ABN, the date, a description of what was sold, and the GST amount or a statement that the total includes GST.
GST-inclusive vs GST-exclusive
GST-inclusive means the price includes the 10% tax. This is the price a consumer pays and the price that must be displayed to consumers. GST-exclusive means the price before GST; it is common in business-to-business quotes, wholesale price lists and internal costing. The difference is not just presentation: it changes the amount of GST you remit and the input tax credits you can claim.
A registered business charges GST on its taxable sales (output tax) and claims credits for GST paid on business purchases (input tax). The net amount is reported on the business activity statement. If input tax credits exceed output tax, the business receives a refund. GST is not a cost to the business itself unless it is not registered or the purchase is for private use.
Common GST amounts
The table starts from a GST-exclusive price and shows the 10% GST and the resulting inclusive total. Use the calculator above to work the other way, from an inclusive total back to the exclusive price.
| Excluding GST | GST at 10% | Including GST |
|---|---|---|
| $100.00 | $10.00 | $110.00 |
| $250.00 | $25.00 | $275.00 |
| $500.00 | $50.00 | $550.00 |
| $1,000.00 | $100.00 | $1,100.00 |
| $1,100.00 | $110.00 | $1,210.00 |
| $2,500.00 | $250.00 | $2,750.00 |
| $5,000.00 | $500.00 | $5,500.00 |
Need an invoice check? Enter the inclusive total in the calculator and choose “Remove GST”. It will return the exact exclusive amount and GST.
GST and income tax are different
GST is a consumption tax collected on behalf of the ATO, not part of your taxable income. If you are a sole trader, you report your business income excluding GST and claim expenses excluding the GST you can credit. Registering for GST does not change your income tax rate, but it does add reporting and cash-flow obligations.
For a view of the income tax on your business or salary income, use the salary calculator. If you are weighing up contracting, thecontractor calculator compares ABN and PAYG income and shows how GST registration affects the amount you invoice.
Questions
GST Calculator Australia FAQs
Quick answers about how this calculator works and what it includes.
How do I add GST to a price?
Multiply the GST-exclusive amount by 10%. A $1,000 price before GST becomes $1,100 with GST, and the GST component is $100. To go the other way, divide the GST-inclusive amount by 1.1 to get the exclusive amount, then subtract it to find the GST.
How do I remove GST from a total?
Divide the GST-inclusive amount by 1.1. For $1,100 including GST, the exclusive amount is $1,000 and the GST is $100. Do not simply subtract 10% from the inclusive figure: 10% of $1,100 is $110, which would give the wrong answer.
What is the GST fraction for 10%?
The GST component of an inclusive price is 1/11 of the total, because the inclusive price is 110% of the exclusive price. For $1,100, one eleventh is $100. Dividing by 11 is a quick way to extract the GST when the rate is 10%.
Should I quote prices including or excluding GST?
Business-to-consumer prices must be displayed inclusive of GST. Business-to-business quotes are often shown excluding GST, with the GST amount and total stated separately. Whatever the format, the tax invoice must show the GST amount clearly once the business is registered.
When must a business register for GST?
You must register when your GST turnover reaches $75,000 in a 12-month period, or $150,000 for a non-profit. Taxi and ride-share drivers must register from their first dollar. Voluntary registration is possible below the threshold but brings reporting obligations.
Are all goods and services subject to GST?
No. GST applies at 10% to most goods and services, but some are GST-free, including most basic food, medical services, education, childcare and exports. Input-taxed supplies such as residential rent and some financial services do not include GST and generally do not allow input tax credits.
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