About GST Calculator App
An independent Australian site with free GST tools for businesses, sole traders and shoppers.
Why This Site Exists
Most GST errors are not arithmetic errors. They happen because someone did not know which figure to start from, or what the result meant for their invoice or BAS. Our GST calculator and the other tools on this site give you the number and explain what it means for your situation.
Who Builds the Tools
Yevgeniy Kuleshov — Technical Architect & Lead Developer
I am a web developer and technical architect. I am not a registered tax agent, BAS agent or accountant. My role is technical: I turn the rules the ATO publishes into tools that give the same result every time and show how they reached it. Every rule we use, and how we test it, is listed on the methodology page.
Our Principles
Free, funded by advertising
There is no paid tier. Ads never change a result or which tool we recommend.
Your figures stay on your device
Calculations run in your browser. We do not ask for your ABN, TFN or bank details, and we do not store what you enter.
Independent
We are not connected to, endorsed by or acting for the ATO or any government body.
Corrections are welcome
If a result does not match your tax invoice or accounting software, send us the inputs. If we are wrong, we fix every tool that uses the same rule.