Updated 8 November 2026

Effective November 2026

People use our calculators to price their work, check invoices and prepare their BAS, so accuracy comes first. This page explains how we research, check and update what we publish.

For GST rules, thresholds and explanations we use primary sources only:

• The Australian Taxation Office (ATO) website, rulings and published examples
• Legislation, mainly the A New Tax System (Goods and Services Tax) Act 1999
• Other government sources, such as business.gov.au

Third-party calculators, news articles and forums can point us to a change, but we never take a rule from them without confirming it at the source.

1. Implementation. The GST formulas live in code, separate from the content system, so editing a page can’t change a calculation by accident.
2. Testing. Every calculation has automated tests, including rounding to the cent, amounts with cents, zero, custom rates and invalid input. Results are checked against hand-worked examples.
3. Review and approval. A change is reviewed before it is published, and every version is kept in the project history so it can be rolled back.
4. Honest limits. The calculator applies the GST formulas to the amount you enter. It doesn’t decide whether a sale is taxable, and our pages say so.

Guides are written for the reader’s actual question, checked against the same primary sources, and dated. Each guide lists its sources and its last review date. We don’t invent statistics, credentials or quotes, and we don’t list qualifications nobody holds.

We are not affiliated with the ATO or any government agency, accounting firm or software provider. Advertising never decides what we say about GST or a product.

AI tools may help with research, organisation and proofreading. They are never used to publish automatically, and every figure is checked by a person before it goes live. See our AI content policy.

We review our GST content at least once a year, and whenever the ATO announces a change to GST rules or thresholds.

If a figure looks wrong, please tell us. Include the amount, whether you chose Add GST or Remove GST, the rate, and a link to the official source if you have one. Email editorial@gstcal.com.au. We treat errors in figures as our top priority.