Editorial policy

What we publish, and what we will not

OzCalc publishes calculators and explanatory guides for everyday Australian arithmetic: pay and tax, housing costs, household bills, working days and unit conversions. There are currently 55 calculators and 21 guides.

We do not publish a calculator until it produces a correct result, shows the formula it used, states its assumptions, works through an example and cites a source. A page that only exists to occupy a search term does not get published. That rule is enforced in the codebase rather than by good intentions — the test suite fails the build if a calculator is missing its explanation, its worked example, its assumptions, a source with a secure URL, or at least one answered question.

Which sources we treat as authoritative

Where a number is set by government, we take it from the body that sets it and we link to that page. In practice that means:

• The Australian Taxation Office for income tax rates, offsets, the Medicare levy and surcharge, study and training loan thresholds, GST and the superannuation guarantee.
• Moneysmart, published by ASIC, for consumer lending and saving concepts such as offset accounts and compound interest.
• The Fair Work Ombudsman for hours of work, leave, overtime and public holidays.
• State and territory consumer or tenancy authorities where the rule is set by state law rather than nationally — residential tenancies being the clearest example.
• The National Measurement Institute, BIPM and NIST for units and physical constants.

We do not cite other calculator websites, content farms, or AI-generated summaries as sources for a rate or a threshold. Where a figure is genuinely uncertain or varies by circumstance, we say so on the page instead of picking a number to look decisive.

How rates are stored and reviewed

Regulated figures are not typed into the page text. They live in versioned datasets in the codebase, one per financial year, each recording the source URL, the period it applies to and the date it was last reviewed. The calculators and the guides both read from those datasets.

The practical effect is that a threshold quoted in a guide and a threshold used in a result cannot disagree. It also means a tax year can be added without rewriting the explanations, and that every page can honestly display when its underlying figures were last checked.

1. A figure is taken from the responsible authority and recorded in a dataset with its source URL and effective period.
2. The calculation is implemented against that dataset and covered by unit tests, including edge cases such as threshold boundaries and zero income.
3. The explanation, assumptions, worked example and questions are written to match what the code actually does — including its simplifications.
4. Around the start of a financial year, and whenever an authority announces a change, the datasets are re-checked and the review date is updated.
5. External links are periodically re-checked so that a citation still resolves to the page it claims to cite.

Being explicit about limits

Every calculator states its assumptions, because a general tool cannot know your circumstances. A salary calculator does not know about your salary sacrifice arrangement, your investment income or your private health cover. A loan calculator does not know your lender’s fees or how it treats a rate change mid-month.

Rather than hide that, each page lists what it assumes and what it ignores, and points at the official source that settles the question. Where a result could reasonably be mistaken for a quote or for advice, we label it as an estimate. See the disclaimer for the full statement.

Corrections

If a rate is out of date, an explanation is unclear or a result looks wrong, we want to know. Reports go to the contact page or hello@ozcalc.com. The most useful report names the calculator and the inputs that produced the problem.

Substantive corrections to a calculation are made in the code and the dataset, which updates the review date shown on the page. We do not quietly change a figure and leave the review date untouched. Please do not include private financial or identifying information in a report; we do not need it to reproduce an arithmetic problem.

Advertising and independence

The site is free and is funded by advertising. Advertisers have no input into which calculators exist, what the explanations say, or what a result shows. No calculator is weighted toward a product, and we do not accept payment for a favourable explanation or for a link inside editorial content.

Ads are kept out of inputs and results so that an advertisement cannot be mistaken for part of a calculation. The privacy policy lists the advertising and analytics services used and the choices available to you.

Who writes this

OzCalc is independently operated. Calculators, explanations, source reviews and correction reports are handled as a single product by the same small team, rather than being commissioned from an anonymous content marketplace. There is more on the site’s scope and limits on the about page.

This policy was last updated 7 September 2026. The site was last deployed 7 September 2026.