How these figures are worked out

The rule

A figure appears here only when it has been read from a primary source: the legislation on the Federal Register of Legislation, or the ATO’s, Fair Work’s or the Australian Business Register’s own published material. Summaries written by other websites are not sources, however confident they sound. Building this site turned up several widely repeated figures attributed to the wrong instrument, one count of “seven” requirements that is actually eight, and an official formula whose published image text is garbled — each of which a summary would have carried forward.

Where something cannot be verified, it is left out rather than hedged. The remaining gaps are listed at the bottom of this page, by name.

Each tool, and what it rests on

The instruments, by compilation

Legislation is cited by the compilation actually read, because “the GST Act” has been amended over a hundred times and a section number alone does not say which version.

ATO pages are cited on each tool with the ATO’s own “last updated” date, so you can see how fresh the underlying page is rather than just how fresh this one claims to be.

Six details that decide whether an answer is right

Most of what separates these tools from the pages that rank for the same terms is a single line of the source that the others skipped. These are the six that matter most.

• GST rounds once, to the tax. Section 9-90 rounds the GST to the nearest cent, half a cent upwards. The engine rounds that figure and derives the other side by subtraction, so the three figures always reconcile. Round each independently and a bookkeeper finds a cent that nobody can explain.
• The GST registration threshold lives in the regulations. The Act says $50,000 and lets the regulations specify more; the regulations specify $75,000. It can change without an Act of Parliament, so it is dated here rather than treated as a constant.
• The Division 7A rate is this year’s, every year. Section 109E(6) uses the current year’s benchmark rate, so the minimum repayment is reworked annually. The published series runs from 4.52% to 8.77% inside one seven-year term; a schedule built on a single rate is wrong from its second year.
• G1 on a BAS is stated inclusive or exclusive of GST at the lodger’s choice, indicated on the form. A calculator that outputs one G1 without asking has guessed at half the answer.
• A payslip must not identify paid family and domestic violence leave. Regulations 3.47 and 3.48 require it to be shown as ordinary hours or another payment. The generator will not create the line, because every template that does is walking an employer into a breach.
• Building and construction is outside the TPAR 10% test. Apply the percentage to a builder and it returns a confident, wrong “no”.

How the figures stay right

Every rate lives in a data file that carries its sources, the compilation or page it was read from and the date it was last checked — never hardcoded into a page. Every engine is pinned by automated tests to the source’s own worked examples, listed in the first table above. A change to a rate means changing the data file and the tests together, or the site does not build. The same build refuses glued copy, a palette colour that fails contrast, an FAQ answer that merely repeats the page above it, and any internal link that points at nothing.

Dates are formatted by the site’s own code rather than by the browser’s locale library, because on a page whose whole product is a date, the output cannot be allowed to vary with which operating system renders it.

What each tool does not do

• GST calculator: does not classify your products — whether a supply is taxable, GST-free or input taxed depends on what it is, and the food rules in Schedules 1 and 2 are famously specific. Does not handle imports, the margin scheme or second-hand goods. Applies the single-supply rounding in s 9-90(1); the several-supplies rule in s 9-90(2) is used by the invoice generator.
• BAS calculator: the GST section only. PAYG withholding, PAYG instalments, FBT, luxury car tax, wine equalisation tax and fuel tax credits are other parts of the same form and are not here.
• BAS due dates: applies the weekend rule and, once you select a state, that state’s public holidays. Regional holidays are not applied — see the gaps below.
• Division 7A: does not test whether a payment is a Division 7A loan at all, does not compute the section 109Y distributable surplus cap (it needs the company’s accounts), and does not apply section 109R, which disregards repayments funded by re-borrowing.
• Invoice and quote generators: check what is on the document, not whether what you typed is true. The ABN check is a checksum, not a lookup: it catches a transposed digit and says nothing about whether the ABN is active or registered for GST.
• Payslip generator: does not calculate PAYG withholding. The amount comes from the ATO’s withholding tables, which depend on facts the page does not have, so tax is a figure you enter. It also does not interpret awards or hold leave balances.
• TPAR checker: answers whether you lodge, not what goes in the report or how to file it, and does not cover government entities.

Known gaps, by name

These are the things this site does not publish because they could not be verified from a primary source, or because the data has not been built yet. An unverified figure does not get a cautious hedge; it gets left out until someone reads the source.

• Regional public holidays. The holiday file covers all eight states and territories for 2026 and 2027, read from each government’s own list, but it carries state-wide days only. Regional days are excluded and named in the file: Queensland and Northern Territory show days, the Tasmanian regional set including Recreation Day, and Victorian councils that move Melbourne Cup. Part-day holidays are excluded too, because a part-day does not make the date a non-business day.
• The ACT list is second-hand. act.gov.au sits behind a bot check that did not clear, and this site does not defeat bot checks, so the ACT dates come from the Fair Work Ombudsman rather than the Territory’s own declaration. Re-verify when act.gov.au is reachable.
• Whose public holidays the ATO means. Its rule says “weekend or public holiday” without saying whose. Applying your own state’s calendar is the natural reading and is what the due dates page does once you select a state, but the ATO does not spell it out.
• Victoria’s 2027 AFL Grand Final Friday. Business Victoria says it is subject to the 2027 AFL schedule and not yet fixed, so it is omitted rather than guessed.
• The weekend rollover for a TPAR. The ATO states the next-business-day rule on its activity statement pages. It was not found on its TPAR pages, so the TPAR page notes that 28 August 2027 is a Saturday and declines to assert the rollover for that form.
• Ride-sourcing as “taxi travel”. Whether it falls within the GST Act’s definition was decided by the Federal Court, not by the Act. The GST page says taxi and limousine, which is what the legislation says, and stops there.
• Next year’s agent lodgment dates. The ATO’s own table says the 2027-28 program dates are to be confirmed when that program is developed. Nothing on this site quotes them.
• Benchmark rates beyond 2027. The Division 7A schedule carries the latest published rate forward for later years and marks every such year as assumed.

Re-verification

Public holidays are re-checked each year as the states publish the following year’s dates, which most do a year or more ahead. The GST and BAS figures are re-checked each 1 July, when the ATO publishes the new financial year’s due dates and lodgment program. The Division 7A benchmark rate is re-checked when the ATO publishes it, in the first days of July. Fair Work regulations are checked when the Federal Register lists a new compilation. Every page shows the date it was last checked, and the sitemap carries the same date so crawlers re-fetch promptly after a change.

Corrections

If a figure here is wrong it should be fixed rather than defended, and a correction with a source attached can be checked the same day. The contact page says how; the about page says who maintains the site.

This page covers how far the figures are checked. Where that checking stops — why none of it is tax advice, and what you take on yourself by acting on a number here rather than asking someone who knows your circumstances — is the other half of the same question, and it is set out in the terms.