Editorial Policy and Methodology

Our principles

• Accuracy over speed. A calculator is not published until its results match worked examples from the official source.
• Show the working. Every calculator explains its formula, assumptions and rate table.
• Plain Australian English. We use everyday words like take-home pay and stamp duty, with the legal term (PAYG withholding, transfer duty) explained alongside.
• Real differences, not templates. State calculators use each state’s own law and rates, not a copy with the name changed.

Sources we use

We use primary sources only:

Topic	Primary sources
Income tax, Medicare levy, HECS-HELP, super caps	ATO, Federal legislation (e.g. Income Tax Assessment Act 1997), Federal Budget papers
Home lending and serviceability	APRA prudential standards and guidance, Reserve Bank of Australia cash rate decisions
Consumer and investment guidance	ASIC and Moneysmart
Stamp duty and land tax	Revenue NSW, State Revenue Office Victoria, Queensland Revenue Office, RevenueWA, RevenueSA, State Revenue Office Tasmania, ACT Revenue Office, Territory Revenue Office NT
Population and economic data	Australian Bureau of Statistics

How a calculator is built

1. Research: collect the current legislation, rate tables and official worked examples.
2. Specify: write down every formula, threshold, rounding rule and assumption before coding.
3. Code: build the calculator in plain JavaScript, using decimal arithmetic (Big.js) so cents are not lost to rounding errors. All rates live in one configuration file that also feeds the page’s reference table.
4. Test: check results against official worked examples and edge cases, such as amounts exactly on a threshold.
5. Review: a second check of the maths, wording and disclaimers before publishing.
6. Publish: each page shows the date its rates were last reviewed and links to the source.

Review schedule

• Every 1 July: all tax, super, HELP and indexed duty thresholds are re-checked for the new financial year.
• After each Federal and state Budget: affected calculators are reviewed and updated once changes are legislated or take effect.
• After RBA and APRA announcements: default interest rates and buffers are reviewed.
• On report: any error report triggers a re-test of the calculator.

Corrections policy

If you find an error, email [email protected]. We acknowledge reports within 2 business days. Confirmed calculation errors are fixed as a priority, and material corrections are noted on the page with the date of the fix.

Use of AI tools

We may use AI tools to help draft explanations, check code and spot inconsistencies. AI is never the source of a rate, threshold or formula. Every figure is checked by a person against the official source before publishing, and a named author is responsible for each page.

Independence and advertising

Advertising funds the site but has no influence on calculator logic, results or content. See our Disclaimer for details.

Frequently asked questions

Where do your rates come from?

Only from primary sources such as the ATO, APRA, the RBA, ASIC Moneysmart and each state and territory revenue office.

How do I report an error in a calculator?

Email [email protected] with the calculator, your inputs and the result you expected. Confirmed errors are fixed as a priority.

Do you use AI to write content?

AI may assist with drafting and code checks, but every rate and formula is verified by a person against the official source, and a named author is responsible for each page.