Why most Payday Super calculators get the date wrong

A Payday Super deadline is counted in business days, and the ATO's definition of a business day is national: a public holiday for the whole of any state or territory removes a day from everybody's count, whether or not you are in that state. Most deadline calculators do not count that way. They count the holidays of the state you select, or they count only the handful of holidays observed everywhere. Either shortcut produces a date that is sometimes right and sometimes a business day out — and a tool that is right most of the time is the hardest kind to catch.

Published 7 September 2026. ATO QC105846 quoted as last updated 10 August 2026 (re-read that evening). No calculator or vendor is named here; the two patterns are described from their published rules so you can recognise them in whatever tool you use.

The rule, in the ATO's words

A business day is any day other than: a Saturday or Sunday; a day that is a public holiday for the whole of any Australian state or territory. This means if there is a state or territory-wide public holiday, that day is not a business day for the purposes of Payday Super, even if you are not in that state or territory. If a public holiday applies to only part of a state or territory (for example, Royal Hobart Show Day), that day is still a business day for Payday Super purposes. ATO, Payment deadlines for Payday Super (QC105846), "Definition of 'business day'"

The wording comes from the Superannuation Guarantee (Administration) Act 1992 s 6(1), which defines a business day as a day other than a Saturday, a Sunday, or "a day which is a public holiday for the whole of any state, the Australian Capital Territory, or the Northern Territory". Three things follow:

• The deadline for a given payday is the same in every state. A Perth client and a Brisbane client paid on the same Friday have the same fund-receipt date.
• Your own state's holiday calendar is not enough. NT Picnic Day, the Victorian Grand Final Friday, Labour Day in NSW, the ACT and SA, the Queensland King's Birthday and Canberra Day all remove a business day from a Western Australian employer's count.
• A holiday that applies to only part of a state does not count — even though it is a real holiday where you are.

Mistake one: counting only your own state's holidays

This is the most common design. The tool asks which state or territory you are in and excludes that state's public holidays, treating every other state's holidays as ordinary business days. It feels right — it is how leave, payroll and award calculations work — and it is exactly what the ATO's definition says not to do.

The ATO's own worked example in QC105846 is the case this gets wrong: a payday of Thursday 30 July 2026 for an employer outside the Northern Territory. Seven business days lands on Tuesday 11 August because Monday 3 August is Picnic Day, a holiday for the whole of the NT. A calculator set to WA, NSW, Victoria or anywhere else counts 3 August as a working day and gives Monday 10 August — one business day early. Early is the harmless direction; the same design errs late whenever it excludes a day in your own state that the Act does not, such as a holiday that only part of the state observes.

The same shape recurs whenever another state's holiday falls inside the window. A Perth payday of Friday 2 October 2026 is due Wednesday 14 October, because Monday 5 October is Labour Day in NSW, the ACT and SA and the King's Birthday in Queensland. A WA-only count has no holiday that week and gives Tuesday 13 October. A client who pays on the 14th believing the tool is late; a client who pays on the 13th is fine, but only by accident.

Mistake two: counting only national holidays

The second design excludes only the days observed in every jurisdiction — New Year's Day, Australia Day, Good Friday, Easter Monday, Anzac Day, the Christmas period — and treats every state-declared day as a business day. It gives the same answer in every state, which looks like the ATO's "no state deadline" position, but for the wrong reason: it is missing every state-wide holiday rather than counting all of them.

For the Perth payday of Friday 25 September 2026 worked below, a national-only count arrives at Tuesday 6 October rather than the correct Wednesday 7 October. Paying a day early costs nothing; the problem is that the same tool, applied to a run where a state holiday sits at the end of the window, will show a deadline a day later than the truth — and it cannot tell you which of the two it has done.

Worked example: a Perth employer, payday Friday 25 September 2026

Count seven business days after the payday. The days that are not business days in that stretch are the weekends, Monday 5 October (Labour Day in NSW, the ACT and SA; King's Birthday in Queensland) — and, on paper, Monday 28 September, the WA King's Birthday, which is dealt with below.

With a three-business-day clearing-house buffer the send-by date is Thursday 1 October. The free checker gives the same two dates and lets you set your clearing house's own buffer.

What each shortcut says for this payday:

• National-only: counts Monday 5 October as a business day → Tuesday 6 October. One day early.
• WA-only: skips Monday 28 September (the state's King's Birthday) and counts Monday 5 October → Wednesday 7 October. The right date, reached by two errors that happen to cancel. The same tool gives the wrong date on 2 October (above) and on 30 July, where nothing cancels.
• NSW-, Queensland-, SA- or ACT-only: those four share the 5 October holiday, so a state-only tool set to one of them also lands on 7 October for this payday. Set to Victoria, Tasmania or the NT — none of which has a holiday that week — it gives Tuesday 6 October.

Why 28 September does not count even for a WA employer: the WA Government's own public-holidays page says the City of Karratha and the Town of Port Hedland observe the King's Birthday on a different date "instead of" the state date, which "is not a public holiday in these regions" — so it is not a holiday for the whole of WA, and s 6(1) does not exclude it. Melbourne Cup Day in Victoria fails the same test because non-metropolitan councils may replace it, and several do. The reasoning and sources are in the public holidays guide. Counting either day would show a deadline one business day later than the truth; SuperDue takes the earlier date.

How to tell which kind of tool you are looking at

• Does it ask for your state before it will compute a date, and does the date change when you change the state? Under the ATO's rule the fund-receipt date for a given payday is identical everywhere; a tool whose answer moves with your state is counting holidays per state.
• Enter a payday of Thursday 30 July 2026 with your own state selected. The ATO's answer is Tuesday 11 August. Monday 10 August means Picnic Day was not counted.
• Enter Friday 2 October 2026. Wednesday 14 October is right; Tuesday 13 October means the 5 October holidays were not counted.

What to do about it

• Count against one national list of whole-of-state holidays, for every client, whatever state they are in. The public holidays guide lists every such day for 2026–27 and the ones that look like they count but do not.
• Use the 2026–27 deadline calendar for a standard cycle — every weekly, fortnightly and monthly payday with its send-by and fund-receipt date, subscribable as an .ics feed — or the free checker for a specific run, including the 20-business-day new-employee window and out-of-cycle payments.
• If you keep your own spreadsheet, test it with the two paydays above before you trust it for a quarter.

Figures and dates here are planning estimates, not tax, legal or financial advice. Confirm anything that matters with the ATO or your registered tax or BAS agent.

Planning information, not tax, legal or financial advice. The legal test is the date the fund receives the money with the information needed to allocate it. Confirm anything that matters with the ATO or your registered tax or BAS agent. Sources are linked in the text; ATO pages are quoted as at the date shown at the top of this guide.