GST calculator

Add 10% GST to a price, or work out how much GST is already sitting inside a GST-inclusive total. Free, no sign-up, and it does the awkward direction correctly.

$
Price excluding GST
$150.00
GST (10%)
$15.00
Total including GST
$165.00

The mistake worth avoiding

Removing GST is not the same operation as adding it. If a client pays you $165 including GST, the GST is $15 - the total divided by 11. Taking 10% off $165 gives $16.50, which is a different number and the wrong one. It is an easy slip to make at BAS time, and it under-reports what you actually collected.

Common questions

How do I add GST to a price in Australia?
Multiply the GST-exclusive price by 1.1. A service priced at $150 excluding GST becomes $165 including GST, of which $15 is GST.
How do I work out the GST inside a GST-inclusive price?
Divide the GST-inclusive total by 11. On a $165 GST-inclusive price the GST is $15. Taking 10% off the total instead gives $16.50, which is wrong and under-reports the GST you have collected. This is the single most common GST arithmetic error.
Do I have to charge GST as a sole trader?
Only if you are registered for GST. Registration is compulsory once your business turnover reaches $75,000 in a 12-month period ($150,000 for non-profits), and optional below that. If you are not registered you do not charge GST and you cannot claim GST credits on purchases.
Should I show my prices including or excluding GST?
If you sell to the public, Australian Consumer Law requires the total price a consumer pays to be shown prominently, so consumer-facing prices should be GST-inclusive. Business-to-business pricing is commonly quoted excluding GST, with GST added at invoice. Whichever you choose, say which it is.
What GST rate applies in New Zealand?
New Zealand GST is 15%. To find the GST inside a GST-inclusive New Zealand price, divide the total by 7.667 (or multiply by 3 and divide by 23).

General information only, current at the time of writing. It is not tax advice and does not account for your circumstances. For anything that matters, check with your accountant or the ATO.

Stop doing this by hand on every invoice

BookAndGo issues proper tax invoices with your ABN and the GST calculated for you, at 10% for Australia or 15% for New Zealand, and marks them paid when the money lands. If you are not registered for GST, it simply leaves GST off.

  • Sequential tax invoices with your ABN and business details
  • GST shown correctly, or omitted entirely if you are not registered
  • Issued automatically when an appointment is completed
  • Receipts sent on payment, without you chasing
See how invoicing works
Tax invoice checkerDoes your invoice meet the ATO's requirements?Booking software with GST invoicingTax invoices with your ABN, issued automaticallyAustralian data residencyWhere your business data actually lives