GST Calculator (Add or Remove GST)

Add GST to a price, remove GST from a total, or find the GST component of a GST-inclusive price.

Add GSTRemove GST

GST-free item (0%)

Price excluding GST

Excluding GST–

GST–

Including GST–

Fig. 1 GST at –

Was this helpful?

Every formula is tested against worked examples, including official ones. How we check

Total paid	GST inside	Before GST
$10.00	$0.91	$9.09
$20.00	$1.82	$18.18
$50.00	$4.55	$45.45
$100.00	$9.09	$90.91
$200.00	$18.18	$181.82
$500.00	$45.45	$454.55
$1,000.00	$90.91	$909.09

Fig. 2 Common amounts at 10%.

Last checked 04/11/2026. Sources: Australian Taxation Office: GST.

Guide

How GST is calculated

GST in Australia is 10% on most goods and services.

Add GST: multiply by 1.1. $500 + GST = $550, of which $50 is GST.

Remove GST: divide the GST-inclusive price by 1.1. $1,100 including GST is $1,000 plus $100 GST.

GST component: divide the GST-inclusive price by 11. A $1,000 GST-inclusive price contains $90.91 GST, not $100. Taking 10% off a GST-inclusive price is a common mistake.

GST-free items

Some sales are GST-free, for example most basic food, some health and education services, and exports. Turn on GST-free to show a price with no GST.

Prices and tax invoices

Prices shown to consumers generally include GST. Businesses registered for GST must charge it on taxable sales and show it on tax invoices. Registration is required from $75,000 GST turnover (the ATO has the detail).

Common questions

How do I calculate the GST in a price?

Divide the GST-inclusive price by 11. For $1,100 that is $100; for $1,000 it is $90.91.

Why not just take 10% off?

Because GST is 10% of the price before GST, not of the final price. 10% of $1,100 is $110, but the GST in it is $100.

Has the GST rate changed?

GST has been 10% since it started on 1 July 2000. The ATO publishes any changes.