Methodology & Sources

Source authorities

All tax rules, thresholds, brackets, and rates used across AusTaxTools calculators are taken directly from published Australian Government sources — primarily the Australian Taxation Office (ATO) and Services Australia for benefit-related amounts. State stamp duty, land tax, and payroll tax figures come from each state revenue office.

Update cadence

We review calculators at the start of each Australian financial year (1 July) and again whenever the ATO publishes mid-year changes (e.g., HELP indexation, super caps, Medicare levy thresholds). Every calculator page shows its own "Last updated" date, pulled from the file's last git commit.

Where the math lives

Calculation logic lives in plain TypeScript files under src/utils/ and src/lib/apps/, separated from UI and covered by unit tests. This means every number shown can be traced back to a tested function rather than a hand-coded value in a page template.

Handling ambiguous rules

Where ATO guidance is ambiguous or a user's situation depends on facts we can't know (e.g., partial-year residency, trust distributions, edge-case depreciation), calculators use the most common interpretation and flag the assumption inline. They do not attempt to produce a number that could only be defended with professional advice.

Not financial advice

AusTaxTools provides general information only. It is not tax, legal, or financial advice, and it does not take your personal circumstances into account. For a binding answer, speak to a registered tax agent or financial adviser.