NZ GST Invoice Calculator

Calculate the GST-exclusive amount, 15% GST and GST-inclusive invoice total for a New Zealand taxable sale. This is an arithmetic tool; it does not decide whether a supply is taxable.

Calculate an invoice

Amount before GST (NZD):

Reverse calculation

If the invoice total already includes NZ GST, divide the inclusive amount by 1.15 to find the GST-exclusive amount. The GST component of an inclusive total is inclusive amount x 3 / 23.

Example

A taxable service priced at NZ$1,000 before GST has NZ$150 GST and an invoice total of NZ$1,150.

Worked example: invoicing a repair job

A plumber in New Plymouth finishes a repair and invoices the client $850 plus GST. The GST is $850 x 15% = $127.50, so the invoice total is $977.50 including GST.

The invoice shows the job description, the date, the plumber’s name and GST number, the $850 exclusive amount, the $127.50 GST and the $977.50 total. When the client later checks the invoice, they can confirm the GST with the reverse calculation: $977.50 x 3/23 = $127.50.

What to show on a New Zealand tax invoice

A calculator checks the arithmetic, but a real tax invoice must carry the information IRD requires, and the detail needed depends on the invoice value. As a rule of thumb, include:

Your business name and GST number.
The date and a clear description of the goods or services.
The GST-exclusive amount, the GST charged and the GST-inclusive total.

Keep a copy of every invoice for at least seven years, which is IRD’s record-keeping requirement. Check the current IRD guidance for the exact information rules, because they changed in April 2023.

Invoice information

A calculator can check arithmetic, but an actual tax invoice must contain the information required by New Zealand GST rules. Use current IRD guidance when preparing invoices and records.

NZ GST invoice calculator FAQs

Do I need to be GST-registered to charge GST?
Yes. Only GST-registered businesses charge GST and issue tax invoices. If you are not registered, do not add GST to your prices.

What if I quote a GST-inclusive price?
Show the GST component on the invoice so the customer can see it. Use the reverse calculation above: inclusive amount x 3/23.

Can I claim GST from a supplier’s invoice?
Yes, if you are GST-registered and the purchase is for your taxable activity. You need the supplier’s tax invoice (or the required taxable supply information) to support the claim.

How long do I keep invoices?
At least seven years. IRD can ask to see your records, and without the invoice you may lose the GST claim.

Official source

IRD GST guidance