How to use the GST Calculator
- 1 Choose Add GST if your price excludes GST, or Remove GST if it already includes GST.
- 2 Enter the amount in dollars, for example 100 or 110.
- 3 Read the price excluding GST, the GST and the price including GST in the three boxes.
- 4 Check the line underneath to see the formula used: × 10% to add GST, or ÷ 11 to find it.
Worked example
$110 including GST. The GST is $110 ÷ 11 = $10.00, so the price excluding GST is $110 − $10 = $100.00. Going the other way, adding GST to $100 gives $100 × 10% = $10 GST and a GST-inclusive price of $110.00.
Features
Add or remove in one place
Switch between adding 10% and taking out one eleventh without retyping the amount.
The ATO method
GST is 10% of the GST-exclusive value, so the GST in a taxable price is that price divided by 11, as the ATO explains.
Rounded to the cent
Results are rounded to the nearest cent, ready for an invoice, quote or BAS worksheet.
When to use it
Writing a tax invoice
A sole trader charging $850 for a job adds $85 GST and invoices $935, showing the GST as a separate line as tax invoices require.
Claiming GST credits
A business paid $1,320 for equipment including GST. Dividing by 11 shows $120 of GST that can be claimed as a credit on the BAS.
Checking a price tag
Retail prices in Australia include GST. A $49.95 item contains $4.54 of GST and costs $45.41 before tax.
Frequently asked questions
What is the GST rate in Australia?
10%. It applies to most goods and services sold in Australia, while some items such as most basic food, many health services and education courses are GST-free.
How do I calculate GST from a total?
Divide the GST-inclusive price by 11. For example, $110 ÷ 11 = $10 GST, leaving $100 excluding GST.
Why is it divide by 11 and not 10%?
Because 10% was added to the GST-exclusive price. A $100 price becomes $110, and the $10 GST is one eleventh of $110, not 10% of it.
Do I have to charge GST?
You must register for GST when your business turnover is $75,000 or more a year, or $150,000 for non-profits. Taxi and ride-sourcing drivers must register whatever their turnover.
Does this calculator handle GST-free items?
No. It applies 10% to the amount you enter. Leave GST-free items out of the amount, or work them out separately.
Should prices I show customers include GST?
Yes. Australian consumer law expects prices advertised to consumers to be the total price, including GST. On a tax invoice the GST amount is shown separately, which is what this calculator gives you.
Results are estimates based on the official rates linked above. Confirm important figures with the issuing authority or a qualified adviser before you act on them.
Reviewed by ToolsUnlocked Team · Last updated