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21 corrections

What we have got wrong

A wrong figure matters to whoever relied on it, so nothing here is quietly edited. Each entry says what the site said before, what it says now, and how the error surfaced — that last part being the one worth reading.

This log was not empty on the day it was published, which is deliberate. Every entry below is a real defect found by the checks described on the methodology page, and several of them were found by a check that now runs on every build so the same mistake cannot ship twice.

Rounding drifted by up to a dollar on large amounts

· Every calculator on the site

It said
The rounding helper broke half-cent ties with a nudge that scaled with the value, so on large figures it stopped being a tie-breaker and became an addition: 1c at $5,000,000, 2c at $20,000,000, 10c at $100,000,000.
It says now
There is no nudge at all now. The helper rounds the amount in cents to 14 significant digits — which clears the binary dust a computer adds to decimals without moving the value — and then rounds to the cent, half a cent up. $20,000,000 is not hypothetical here — it is the turnover this site names as the monthly-lodger boundary on the BAS pages. (Until 24 September 2026 this entry said the fix was "a fixed epsilon". It never was; the description was wrong, not the arithmetic. Until 9 October 2026 it was 12 digits, which held every cent only below $10 billion; above that it lost them, rounding to the nearest 10c, and to the dollar above $100 billion. Fourteen holds every cent to a trillion. And until 9 October 2026 the Division 7A calculator and the payslip still kept their own copy of the old nudge: see the entry of that date.)
How it was caught
Probing extreme inputs across every calculator, rather than only the values a typical user would type.

A turnover spike was answered with a flat “No”

· /do-i-need-to-register-for-gst/

It said
With the last twelve months over the $75,000 threshold and the year ahead under it, the page answered a flat "No". Under section 188-10 that case turns on whether the Commissioner accepts the lower projection, so "No" was a green light the arithmetic cannot give. Beneath it the page showed "Headroom before it applies: $0" and offered voluntary registration "below the threshold" to someone whose last twelve months were above it. (Until 24 September 2026 this entry described the case the wrong way round, as current turnover UNDER the threshold.)
It says now
The answer in that case is "Not automatically", with the reason: it depends on the Commissioner accepting the lower projection. The page shows how far the last twelve months went over, and offers voluntary registration only where it is true.
How it was caught
An adversarial review of the whole site that looked specifically at what each page says in its EDGE cases. Structure came back clean; every problem was in the edge-case wording.

Two pages were missing from the machine-readable index

· llms.txt

It said
Two calculators built that day were absent from llms.txt, which the site's own rules have always required to list every page.
It says now
Both are listed, and the file is now checked against the calculator index at build time.
How it was caught
The same adversarial review. It was exactly the manual-step drift the artwork guard already existed to catch, in a step nothing was guarding.

Recipient created tax invoices were described by industry, under rules repealed in 2023

· /tax-invoice-template/ and /invoice-generator/

It said
Both pages said a recipient created tax invoice "is only available for particular industries and arrangements". That was the position under some fifty earlier determinations, most for a particular industry or kind of supply — road transport, vehicle dealers, recyclers, agricultural products and more — which the Recipient Created Tax Invoice Determination 2023 repealed when it commenced on 15 June 2023, the day after it was registered.
It says now
Since then the test is who the buyer is: a government related entity or a large business entity may issue RCTIs for any taxable supply, and any other GST-registered business may where it determines the value of what it buys — in every case with both parties registered and a written agreement. The new recipient created tax invoice page sets the 2023 instrument out in full.
How it was caught
Reading the 2023 determination itself while building that page, rather than a summary of it: the ATO's general tax invoice page still describes RCTIs by the type of goods or services supplied.

The no-tax-invoice floor was printed as $83 including GST

· /invoice-generator/

It said
From the page's launch, its section on small sales said a tax invoice is not required where the value of the supply is $75 or less — "$83 including GST". The $75 was right; the conversion was not. It went through the formatter the site uses for whole-dollar figures, which rounds $82.50 up, so a sale priced between $82.51 and $83.00 read as needing no tax invoice when its value is over $75 and it does. The FAQ on the same page said $82.50.
It says now
It says $82.50, worked out by the GST engine from the $75 in regulation 29-80.01 rather than typed: the regulation measures the value of the supply, which excludes GST, and $75 plus 10% is $82.50 exactly.
How it was caught
A review found the figure typed into the page rather than read from the data file. Checking every place the page printed it turned up two different answers on one page: $82.50 in the FAQ, $83 in the body.

The customer-details requirement was labelled “over $1,000”

· /tax-invoice-template/

It said
The annotated list of tax invoice requirements labelled the fifth one "Your customer’s identity or ABN — over $1,000". Section 29-70(1)(c)(ii) applies where the total price is AT LEAST $1,000, so an invoice for exactly $1,000.00 needs it too. The note under the label, and the rest of the page, said "reaches" or "at or above" $1,000; the label contradicted them.
It says now
The label reads "from $1,000". The figure comes from the same data the invoice generator checks against, and the generator has always asked for the customer at $1,000 or more.
How it was caught
The same review. Reading every sentence that printed the $1,000, in order to render it from the data, found this was the only one that put the line in the wrong place.

Four errors on two pages published the same day, found by that day’s review

· /base-rate-entity/ and /recipient-created-tax-invoice/

It said
Both pages went up on 4 October and were corrected that evening. The base rate entity page said a company "mostly passive" last year franks at 30%, and that a first-year company that turns out "mostly passive" can be taxed at 30%. The line is 80% of assessable income, not half: a company 60% passive is still a base rate entity. The RCTI page said "A $40 RCTI without your ABN is not a valid RCTI", and its large-business option read "in a GST group or joint venture with an entity that has it".
It says now
Both base rate entity sentences say "more than 80% of its assessable income". The RCTI page says the buyer must be identified at any amount, by name OR ABN, as section 29-70(1)(c)(ii) puts it, and that the ATO's guidance is to show both. The large-business option follows the Determination's definition: a GST group member, a business eligible to join such a group or a proposed one, or the OPERATOR of a GST joint venture, not any participant in one.
How it was caught
A fact-check of every legal claim on the day's new pages, run against the readings banked from the Act, the Determination and the ATO. The same review corrected this log's own RCTI entry, which had dated the 2023 repeal to the day the Determination was registered rather than the day after, when it commenced.

The payslip page implied an employee could ask for family and domestic violence leave to be named

· /payslip-generator/

It said
For a few hours on 4 October the introduction said the regulations keep this leave "off a payslip unless the employee asks otherwise", and the section on it said regulation 3.48(3) "allows a different treatment where the employee has asked for one; without that request, these rules hold". Both read as if an employee could ask for the leave to appear. Since the page launched, an FAQ and a paragraph had also said the employee could ask for "a different treatment", without saying what treatment.
It says now
Regulation 3.47, which bars naming the leave, saying a period was taken as it, and showing its balance, has no exception. Regulation 3.48(3) lets an employee ask for the payment to be reported as another particular kind of leave, "other than a period of paid family and domestic violence leave". The page now says exactly that, and the introduction is back to "must never appear", which was right.
How it was caught
A final review read regulation 3.48(3) itself, in the current compilation. The wording had been changed that morning on the strength of our own research notes, which paraphrased the subregulation instead of quoting it, and the paraphrase had dropped the words that matter.

The small business pool wrote an asset off a year too early

· /instant-asset-write-off/

It said
For an asset at or over $20,000, the page said the pool is written off "when the pool’s closing balance falls under $20,000", and its calculator did that: a $21,990 asset was shown written off in full in its first year, and the $45,000 example cleared in three years. The headline beside a pooled asset also read $0.00 deductible this year.
It says now
Section 328-210 of the Income Tax Assessment Act 1997 tests the pool’s balance BEFORE that year’s 15% or 30% deduction, so a pooled asset is never written off in its first year: $21,990 takes $3,298.50 in year one and the remaining $18,691.50 in year two, and $45,000 clears in four years. The headline now shows the first year’s 15%.
How it was caught
A review of the whole site tried the calculator with an asset just over the limit, and the number of years looked one short. Reading section 328-210 itself confirmed it; the ATO summary this was built from does not say which balance is tested.

Every business doing building work was told to lodge a TPAR

· /taxable-payments-annual-report/

It said
The page said a business that provides building and construction services and pays contractors lodges a TPAR "regardless of the share" — "whatever proportion of its income that work represents" — and the checker answered Yes for any business that ticked building and construction.
It says now
The 10% test does not apply to building and construction, but a separate one does: the ATO requires a business PRIMARILY in it, meaning 50% or more of this year’s income or business activity, or of last year’s income. The ATO’s own example is a hardware shop that arranges installations and does not lodge for them. The checker now asks.
How it was caught
Comparing the page with others that rank for TPAR: one mentioned a 50% figure for building. The ATO’s "Building and construction services" page (QC51593) had never been read; the original reading covered only its general "work out if you need to lodge" page.

The Division 7A calculator assumed every loan ran for the maximum term

· /div-7a-calculator/

It said
The calculator offered only "unsecured, 7 years" or "secured, 25 years" and worked every repayment from that maximum. For a loan made in an earlier year, it also showed a balance projected as if exactly the minimum had been repaid every year, labelled as the balance not repaid at the end of last year.
It says now
Section 109E(6) counts the remaining term from the term of the loan itself, which an agreement can set shorter than the maximum — and a shorter term means a bigger minimum repayment, which the old figure understated. The calculator now asks for the agreed term, takes the real balance owing where you know it, and says when a balance is a projection.
How it was caught
Comparing the calculator with the ATO’s own Division 7A tool, which asks for the loan’s term; the definition of "remaining term" in section 109E(6) confirmed it.

A valid ABN was described as failing the check-digit test

· /invoice-generator/

It said
In the tax invoice checklist, the note under "Your ABN" read "this one does not pass the ABR’s check-digit test" whatever was typed — including under a green tick for an ABN that passed. The generator also arrived with the ABR’s own example ABN filled in, which passes the check, so an invoice nobody had edited showed it as met.
It says now
The note says whether the ABN passes, and the ABR’s example ABN is named as an example and not accepted. The business name and ABN start empty.
How it was caught
A walk through the generator in the whole-site review, reading every line it printed.

An invoice with every line GST-free was said to include GST

· /invoice-generator/

It said
With “I’m registered for GST” ticked and every line marked GST-free, the invoice printed “Total includes GST as shown.” under a GST line of $0.00, and the checklist said “Every line on this invoice is taxable, so stating that the total price includes GST satisfies this”.
It says now
That invoice now says “No GST is payable: every line on this invoice is GST-free”, and the checklist says every line is marked GST-free. It is the everyday invoice of a provider who is registered for GST and whose supports are all GST-free, such as NDIS supports that meet the four conditions in section 38-38.
How it was caught
Building the NDIS invoice editor, whose usual case for a registered provider is exactly that invoice.

Prices that include GST could give the wrong total

· /invoice-generator/, /quote-template/, and the editors on /tax-invoice-template/, /sole-trader-invoice-template/, /ndis-invoice-template/ and /construction-quote-template/

It said
With “My prices already include GST” ticked, a business NOT registered for GST had one eleventh taken off every price: $110 typed became a $100 line and a $100 total, under “No GST has been charged”. For a registered business the GST came out of each line, was rounded, and went back on, so seven $1 lines totalled $7.01; and each line showed its price including GST beside an amount excluding it, as “2 × $55.00 = $100.00”.
It says now
The switch shows only while the business is registered, and is ignored otherwise. Prices that include GST total exactly what the lines add up to, the GST is one eleventh of the taxable part rounded once, and each line multiplies out, with the columns marked as including GST wherever there is GST to include. (For about seven and a half hours after that fix, an invoice whose every line was GST-free still carried “inc GST” headings above “No GST is payable”.)
How it was caught
A review of the invoice and quote builds, by testing the editors with prices that include GST on a business that is not registered.

The NDIS claim check said “No line has no date”

· /ndis-invoice-template/

It said
With two or more lines and none of them dated, the check of what an NDIS claim needs said “No line has no date of support.” — which reads as every line having one — beside a check marked as not met. The support item number and price checks said the same of their own fields.
It says now
It says “None of the 2 lines has a date of support.”
How it was caught
A fact-check of every new sentence in the NDIS invoice editor, the day it went live.

Two calculators kept the old rounding, and could show a cent too much

· /div-7a-calculator/ and /payslip-generator/

It said
The 4 September fix to rounding reached the GST engine but not the Division 7A calculator or the payslip, which each kept their own copy of the old tie-break. Some Division 7A minimum repayments were a cent high on ordinary loans: $248,000 over seven years, made in the 2024 income year, showed $48,895.61 where the formula gives $48,895.60495…, which rounds to $48,895.60. From about $5 million the rows also stopped adding up: on $20,000,000 the first closing balance was $17,810,806.07, two cents more than the opening balance less the principal repaid. On the payslip, an hourly rate with more than two decimals could pay a cent too much: 123.48 hours at $135.9227 showed $16,783.74 for $16,783.734996.
It says now
Both round with the site’s one rule, to the nearest cent, half up. Every row of a seven or 25-year Division 7A schedule reconciles to the cent, tested at seven amounts from $1 to $12.3 billion.
How it was caught
A hands-on review entering very large loans, then a fact-check that ran the old and new code side by side and found the same rounding still in the payslip.

The write-off chart sent a large business to a pool it cannot use

· /instant-asset-write-off/

It said
With aggregated turnover of $10 million or more, the answer said the simplified depreciation rules did not apply, but the chart beneath it said an asset of $20,000 or more “goes to the small business pool instead”, and its description said the cost was deducted through the pool “over 0 income years”. A cost past the end of its scale was labelled as the scale’s end: $200,000.00 for a $250,000 asset.
It says now
Where the simplified rules do not apply, the chart says neither the write-off nor the pool is available, and it labels the real cost. (Until the same evening the page also said the general depreciation rules apply instead, a claim this site had not checked against a source; it now says only what is verified.)
How it was caught
A hands-on review entering a turnover over $10 million and an asset over the limit.

The registration chart labelled a large turnover as $750,000

· /do-i-need-to-register-for-gst/

It said
The chart beneath the answer stops at ten times the threshold, and it labelled any turnover beyond that as the end of the scale: $5,000,000 was marked “$750,000”, on the chart and in its description for screen readers.
It says now
The marker still stops at the end of the scale, but its label gives the real turnover.
How it was caught
A hands-on review entering turnovers of $5 million and more.

A decimal comma was read as thousands

· Every calculator that takes an amount

It said
A comma was taken as a thousands separator wherever it fell, so “40,50” — a decimal comma, as much of the world writes it — was read as 4,050, a hundred times too much, without a word.
It says now
A comma is read only between groups of three digits (“1,000”, “12,345.67”). Anything else with a comma is flagged as unreadable, so it can be retyped.
How it was caught
A hands-on review typing a rate as “40,50” into the payslip.

The payslip could pay a negative figure, or stop following the rate

· /payslip-generator/

It said
Negative hours turned a line into a flat amount equal to its rate, so −76 hours at $32 paid $32 into the gross; hours typed so the box could not read them (“--3”) did the same; a negative rate printed “76 × −$32.00 = $0.00”; and a negative deduction printed outside the total. Separately, emptying the hourly rate box and typing a new rate left the ordinary-hours line behind (“$40.00 an hour” above 76 × $3.00 = $228.00), and typing a new rate could capture another line whose rate matched a figure on the way: an overtime line at $48 followed the rate once 48.5 had been typed.
It says now
A negative or unreadable figure is flagged on its box and its line left off the payslip, the rate and contribution boxes flag a figure they cannot read, and only the ordinary-hours line follows the rate — however it is retyped, and until its own rate is changed.
How it was caught
Two hands-on reviews typing negative, unreadable and retyped figures into every box.

The GST column of a mixed invoice did not say why it differed from the total

· /invoice-generator/ and the invoice template editors

It said
Each line’s GST is rounded to the cent while the total is worked out unrounded and rounded once, under section 9-90(2)(a), so the column can be a few cents away from the total — with prices including GST, seven taxable $1 lines show 7 × $0.09 = $0.63 under a GST total of $0.64 — and the invoice did not say why. For a few hours on 9 October the total was instead shared out across the lines so the column added up; that put $0.10 on one of seven identical lines and could show $0.00 against a taxable line, and it was withdrawn.
It says now
Each line shows its own GST, rounded to the cent, and where the column differs from the total the invoice says why.
How it was caught
Code and hands-on reviews adding up the GST column, and a fact-check of the change that first tried to make it add up.

Found something wrong?

Tell us and it gets fixed and logged. Every calculator names the source it was checked against and the date it was checked, which should make an error easy to point at — start from contact. What we already know we do not model is listed on the methodology page rather than left for you to discover.