InvioGST Calculator AUAdd or Remove 10% GST
Easily add or subtract 10% GST for your Australian invoices and quotes, then use the same numbers when you build a tax invoice.
How much is GST in Australia?
The standard Australian GST rate is 10% for most goods and services.
Add GST formula
GST-inclusive total = amount × 1.1. GST only = amount × 0.1.
Remove GST formula
GST-exclusive amount = total ÷ 1.1. GST component = total ÷ 11.
AU GST Calculator (10%)
Instantly add or subtract GST for Australian invoices.
Common Australian GST Calculator Examples
These are the exact calculations tradies and sole traders usually need before creating a GST tax invoice, quote, or BAS record.
Add GST to $100
$100 × 1.1 = $110 total, with $10 GST.
Remove GST from $110
$110 ÷ 1.1 = $100 before GST.
Find GST inside $110
$110 ÷ 11 = $10 GST component.
Calculate GST only
GST-exclusive amount × 0.1 gives the GST amount.
How to Calculate GST in Australia
The standard GST rate in Australia is 10%. Whether you are a sole trader, contractor, or small business, you need to calculate it correctly so the invoice totals and GST breakdown line up with what the ATO expects.
Formula to Add GST in Australia (Exclusive to Inclusive)
If you have a price before tax and need to add GST:
Formula to Remove GST in Australia (Inclusive to Exclusive)
If you have a total price and need to work backwards to find the amount before tax:
Why "Divide by 11"?
Because 10% is added on top of a base of 100%, making the GST-inclusive total 110% of the original price. GST is therefore 1/11 of the total (10 out of every 110), which is simpler than NZ's 3/23 - Australia's round 10% rate keeps the fraction clean.
Need to understand exactly what an ATO-compliant tax invoice must show? See our Tax Invoice Requirements AU guide, or check the free AU invoice template for a ready-made GST-ready layout. Invoicing without an ABN? Read about the 47% no-ABN withholding rule before you send your next invoice.
GST Calculator for Sole Traders and Small Businesses
GST-registered sole traders and small businesses must add 10% GST to invoices and remit it to the ATO. Use this calculator when you are quoting a job to show the GST-exclusive price alongside the GST-inclusive total, or when you need to confirm the GST component on a supplier receipt for your BAS.
The most common use case is quoting: enter your labour or materials cost, hit "Add GST", and you have the exact figures to put on your quote or tax invoice. Once you have your totals, you can move straight to invoicing. Need a ready-made layout? Download our free tax invoice template to drop your calculated totals straight into a GST-ready document, or use Invio invoicing software to create and send a GST invoice in under 60 seconds.
If you are not yet registered for GST, the calculator is still useful for understanding the tax component in supplier invoices and for planning ahead when you approach the A$75,000 GST registration threshold.
New to invoicing as a sole trader? Our step-by-step invoicing guide covers exactly what to put on every invoice, and Sole Trader Expenses Australia lists what you can claim back before you hit the GST threshold.