New Build GST Calculator NZ

This calculator works out how much GST sits inside a New Zealand new build price, and shows you the figure both with and without that GST added. New builds sold by a GST-registered developer or builder have 15% GST built into the price, which is different from most existing homes bought from private owners, where no GST applies at all. You simply enter the price and tell the calculator whether that figure is GST inclusive (the usual way a new build is advertised) or GST exclusive (a contract quoted "plus GST"). From there it returns three numbers: the GST portion itself, the GST-exclusive build cost, and the GST-inclusive price, using the standard formula of price times 3 divided by 23 to strip GST out of an inclusive figure, or adding 15% to a GST-exclusive one. This is useful for buyers comparing a new build against an existing home, and for builders and developers quoting or checking a contract, since a price quoted "plus GST" is 15% higher than it first looks. Always check with the seller, builder or your accountant whether a quoted price includes GST before you sign anything, as assuming the wrong basis can leave you well short of what you actually need to pay. Figures shown are an estimate only.

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$
$110,870
GST in the price (15%)
GST exclusive$739,130
GST inclusive$850,000

GST is 15%. The GST portion of an inclusive price is price x 3 / 23. New builds from a registered developer include GST; most existing homes sold privately do not. Always confirm whether a build contract is quoted including or excluding GST. Estimate only.

How it works

If the price you enter is GST inclusive, the calculator finds the GST as price times 3 divided by 23, and the exclusive price as the rest. If the price is GST exclusive, it adds 15% to get the inclusive price. This matters most for build contracts, where a figure quoted "plus GST" is 15% more than it first appears, and for buyers comparing a new build (GST included) with an existing home (no GST).

Worked example

On an $850,000 GST-inclusive new build, the GST portion is about $110,870, leaving a GST-exclusive figure of about $739,130. If a builder instead quoted $850,000 plus GST, the inclusive price would be $977,500.

Related calculators

Data sources: the rates and thresholds on this page are maintained against Inland Revenue. Figures are checked twice monthly.

Frequently asked questions

Does a new build include GST?

Yes. A new build (a new home or section sold by a GST-registered developer) includes 15% GST in the price, unlike most existing homes sold by private owners, which are not subject to GST. So the headline price already has the GST built in.

How do I find the GST in a new build price?

The GST portion of a GST-inclusive price is the price multiplied by 3 and divided by 23. This calculator does that, and also shows the GST-exclusive build cost, which is useful for builders and developers pricing contracts.

Do I pay GST on top of a new build price?

Usually the advertised price is GST-inclusive, so you do not add GST on top. Always check whether a build contract is quoted including or excluding GST, as the difference is large.