Free Australian GST Calculator

Add or remove 10% GST in seconds and see the net amount, GST and total. No formulas, no spreadsheets.

Amount (AUD)

GST rate (standard is 10%)

Custom

GST treatment

Result

Total amount incl. GST

$ 1,100.00

Net amount (ex-GST) $1,000.00

GST @ 10% $100.00

$1,000.00
Net + $100.00
GST = $1,100.00
Total

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How to calculate GST in Australia

This free Australian GST calculator does the maths in three quick steps. Use it to add GST to a price or remove GST from a price that already includes it.

Enter the amount

Type the price of your goods or service in AUD.

Choose the GST rate

Use 10% (standard), 0% (GST-free) or set a custom rate.

Add or remove GST

Pick whether the amount excludes or includes GST. The result updates instantly.

What is GST in Australia?

The Goods and Services Tax (GST) is a broad-based, consumption tax of 10% on most goods, services and other items sold or consumed in Australia. It was introduced on 1 July 2000 and is administered by the Australian Taxation Office (ATO), applying uniformly across all states and territories.

GST-registered businesses collect GST on their sales, claim credits for the GST on their purchases (input tax credits), and report the difference to the ATO on a Business Activity Statement (BAS).

Australian GST categories

Category	Rate	Typical examples
Taxable	10%	Most goods & services sold in Australia. You charge GST and can claim credits on related costs
GST-free	0%	Most basic food, many medical & health services, some education and childcare, and exports. No GST charged, but you can still claim credits
Input-taxed	No GST	Residential rent and most financial supplies. No GST charged, and you cannot claim credits on related costs
Out-of-scope	N/A	Supplies that aren't connected with Australia or aren't taxable supplies

GST-free vs input-taxed: both mean no GST is charged to the customer, but the difference matters for credits. Businesses making GST-free supplies can still claim GST credits on related purchases, while those making input-taxed supplies generally cannot. Always confirm your supply's classification with the ATO or a registered tax agent.

Who needs to register for GST?

You must register for GST with the ATO if any of these apply:

Mandatory

Your business has a GST turnover of $75,000 or more in a 12-month period (current or projected).

Non-profit

Non-profit organisations register once turnover reaches $150,000. Taxi and ride-sourcing drivers must register regardless of turnover.

GST calculation formula (with examples)

Prefer to see the maths? These are the exact formulas the calculator uses, with worked examples at the Australian standard rate of 10% on $1,000.

Read this first

In every formula below, “GST Rate” is the percentage you charge, which for the standard rate is 10. To avoid mixing whole numbers and decimals, all formulas keep the same form: GST Rate ÷ 100. So at 10%, GST Rate ÷ 100 = 0.1 and 1 + GST Rate ÷ 100 = 1.1.

+Adding GST price excludes GST

GST = Net Price × (GST Rate ÷ 100)

Total = Net Price + GST

Example: net $1,000 at 10%

GST= 1,000 × (10 ÷ 100) = $100.00

Total= 1,000 + 100 = $1,100.00

−Removing GST price includes GST

Net Price = Inclusive Price ÷ 1.1

GST = Inclusive Price ÷ 11

Example: $1,100 including GST

Net= 1,100 ÷ 1.1 = $1,000.00

GST= 1,100 ÷ 11 = $100.00

=Quick total net → total in one step

Total = Net Price × 1.1

GST = Total − Net Price

Example: net $1,000 at 10%

Total= 1,000 × 1.1 = $1,100.00

GST= 1,100 − 1,000 = $100.00

The reverse trick: at 10%, GST is exactly 1/11 of a GST-inclusive price, because 10 ÷ (100 + 10) = 1/11. Don't take 10% of the total; that overstates the GST. Figures are rounded to 2 decimal places (cents).

Common GST calculation mistakes

Taking 10% of a GST-inclusive priceOn $1,100 including GST, 10% of the total is $110.00, but the GST inside it is $100.00. Divide by 11, or use Remove GST above.
Adding GST to a GST-free or input-taxed saleCheck how the sale is classified before you add GST. The categories table above and our guide to GST for small business owners explain the difference.
Treating the GST-inclusive amount as your incomePart of a GST-inclusive sale is GST you report to the ATO. Keep sales and GST apart in your books so the amounts on your Business Activity Statement are easy to work out.
Rounding each line differentlyRounding every line and then adding can give a slightly different total than rounding once at the end. Use one method on every invoice.

Frequently asked questions

What is the GST rate in Australia?

The GST rate in Australia is a flat 10% on most goods and services. It was introduced on 1 July 2000 and is administered by the Australian Taxation Office (ATO). Some supplies are GST-free (0%) or input-taxed.

How do I add 10% GST to a price?

Multiply the GST-exclusive (net) amount by 1.1 to get the GST-inclusive total, or by 0.1 to get the GST itself. Example: $1,000 × 1.1 = $1,100, so the GST is $100.

How do I remove GST from a GST-inclusive price?

Divide the total by 1.1 to get the net (GST-exclusive) price, or divide by 11 to get the GST component. Example: $1,100 ÷ 1.1 = $1,000 net, and $1,100 ÷ 11 = $100 GST.

Why divide by 11 and not take 10%?

Because the GST is 10% of the net price, not of the total. The total is 110% of the net, so the GST is 10/110 = 1/11 of the inclusive price. Taking 10% of the total overstates the GST.

What's the difference between GST-free and input-taxed?

Both mean no GST is charged to the customer. The difference is credits: businesses making GST-free supplies can still claim GST credits on related purchases, while those making input-taxed supplies generally cannot.

When must a business register for GST?

You must register once your GST turnover reaches $75,000 in a 12-month period ($150,000 for non-profits). Taxi and ride-sourcing drivers must register regardless of turnover. You can also register voluntarily below the threshold.

Is this GST calculator free?

Yes. The ProfitBooks Australian GST calculator is completely free, needs no sign-up, works on mobile and desktop, and updates instantly as you type.

Can I enter a different GST rate?

Yes. Type any rate in the Custom box to model a different rate. The net amount, GST and total update as you type.

Does the calculator round to the cent?

Yes. The net amount, GST and total are shown to two decimal places, so you can copy them straight onto an invoice.

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Keep your GST in order, every invoice

ProfitBooks helps you raise GST-compliant invoices, track GST collected and paid, and keep your books ready for your BAS, so you spend less time on tax and more on your business.

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This calculator is for general guidance only and reflects the Australian standard GST rate of 10%. It is not tax advice. GST classification (taxable, GST-free, input-taxed) can be complex, so confirm treatment with the ATO or a registered tax agent before lodging your BAS.