NZ / AU Business Day Calculator
New Zealand and Australia public holidays + business-day arithmetic.
Written and maintained by Paul Clark, Redmoon Software · Rules last verified · Sources · Changes & corrections
These calculators are for informational purposes only and do not constitute legal, financial, or professional advice.
How the NZ / AU Business Day Calculator works
The NZ / AU Business Day Calculator runs one date range against both the New Zealand and the Australian public-holiday calendars and reports the two working-day counts side by side, along with the difference and which holidays caused it. Running both at once is the point: a trans-Tasman deadline has two answers, and the useful thing is knowing where they diverge.
The two calendars agree on less than people assume. New Zealand observes Waitangi Day and King’s Birthday on dates Australia does not; Australia observes Australia Day and, in most states, a Queen’s or King’s Birthday on a different date entirely. ANZAC Day is shared. New Zealand applies Mondayisation to several holidays that fall at a weekend, shifting them to the following working day, while Australian practice varies by state. The upshot is that a project spanning both countries can lose a working day on one side and not the other, and the side that loses it changes through the year.
Regional holidays matter as much as national ones. New Zealand’s anniversary days differ by region and Australia’s state holidays differ substantially — Melbourne Cup Day in Victoria, Labour Day on four different dates across the states. Both calendars are selected by default so that a region picker appears for each: choose the NZ region and the Australian state of the two offices and both counts include their local holidays. Leave them on national only and the result says so. Office closures you add as custom dates are applied to both sides, and the include-start and include-end boxes decide whether the two endpoint days are counted.
Worked example
The first quarter of 2026, 1 January to 31 March, gives 61 working days in New Zealand against 62 in Australia on the national calendars: New Zealand loses New Year’s Day, the day after and Waitangi Day, while Australia loses New Year’s Day and Australia Day. Pick Wellington and Victoria in the region selects and it becomes 60 against 61 — Wellington Anniversary Day on Monday 19 January and Victoria’s Labour Day on Monday 9 March each take one more. The calculator names every holiday responsible, so a one-day discrepancy between two offices explains itself immediately rather than turning into a scheduling argument.
Frequently asked questions
Why do the two counts differ?
Because the national holiday calendars genuinely differ. New Zealand has Waitangi Day and observes King’s Birthday in early June; Australia has Australia Day and observes the monarch’s birthday on a different date in most states. Only ANZAC Day lines up reliably. The calculator names the holidays inside your range on each side so you can see precisely which ones account for the gap.
Are regional holidays included?
Yes, when you choose them. New Zealand’s regional anniversary days are observed in one region and not others, and Australian state holidays vary enough that two offices in the same country can have different working-day counts. Pick the NZ region and the Australian state in the region selects and each count includes them; otherwise both counts are the national baseline, and the result labels them that way.
What is Mondayisation?
A New Zealand rule that moves certain public holidays to the following Monday when they fall at a weekend, so the day off is not lost. It applies to Waitangi Day and ANZAC Day among others, and it means a holiday date on the calendar and the day actually observed can differ. The calculator uses the observed dates, which is what affects a working-day count.
Why do I need to pick a region as well as a country?
Because Australian public holidays are largely state-set and New Zealand anniversary days are regional. Labour Day falls in three different months depending on the Australian state (March, May or October). A national-only count misses all of them, and for most users the regional calendar is the one that actually governs.
What this calculator does not do
A limitation you know about costs far less than one you find after the deadline. These are the specific things this tool cannot work out for you.
- Australian public holidays are largely state-set. A national-only count will miss state holidays such as Melbourne Cup Day or Labour Day, which fall on different dates in different states — pick the region.
- New Zealand regional anniversary days are observed locally and are handled by the region selector, not by the national calendar.
- Matariki is set by a gazetted schedule rather than by formula. Dates are carried to 2052 and the tool warns beyond that.
Where these rules come from
The periods this calculator applies are taken from the primary sources below rather than from secondary summaries. Verify against them before relying on a date that matters.
- Holidays Act 2003 (NZ)
The eleven New Zealand public holidays and the Mondayisation rules.
- Fair Work Ombudsman — public holidays (AU)
National and state public holidays in Australia.
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