I built free Australian tax calculators and published them on GitHub Pages

I've developed a collection of free tax calculators specifically designed for Australian sole traders and published them on GitHub Pages. This accomplishment was part of creating Instant Receipts, a receipt scanning and BAS prep app for Australian sole traders. To make these calculators accessible without any framework, server, or build step, I extracted them into a standalone static site on GitHub Pages, allowing them to function with just HTML, CSS, and JavaScript.

The suite includes six tools, all designed to work seamlessly in the browser—no server interaction or data storage involved. These tools cater to the specific needs of Australian tax compliance:

1. GST Calculator: Apply or remove 10% GST from a price using the 1/11th rule.

2. BAS Calculator: Calculate G1, 1A, and 1B for a Business Activity Statement.

3. Sole Trader Tax Calculator: Determine income tax, Medicare levy, HELP repayment, and take-home pay.

4. Mileage Calculator: Apply the ATO's cents per km deduction (91¢/km for 2026-27).

5. Work From Home Calculator: Apply the ATO's 70¢/hour fixed rate deduction.

6. Invoice Generator: Create a tax invoice including ABN, GST per line, which can be downloaded as a PDF.

The decision to keep these calculators pure HTML/JS was intentional. It eliminates the need for complex setup processes like npm installs or build steps, ensuring anyone can simply open the file and access the tools immediately. This approach prioritizes user accessibility, especially for those who might be hesitant to install software or navigate through build processes. The calculators run entirely in the browser, making them completely secure and private since no data is transmitted to a server or stored anywhere.

Since Australian tax laws are quite specific—ranging from the GST 1/11th rule to the Small Business Income Tax Offset and the ATO's cents per km rates—I had to build each tool from scratch. This work was based solely on the Australian Tax Office's own documentation, ensuring accuracy and relevance for Australian users. For those interested in viewing the source code or learning more about the Australian tax specifics involved, the calculators are available at instant-receipts-pty-ltd.github.io/australian-calculators.