About GSTCalc.nz
Free New Zealand tax calculators for sole traders, contractors, employers, and bookkeepers who need a correct IRD figure fast.
GSTCalc.nz started as a GST add and remove tool. It now also covers PAYE, withholding tax, FBT, provisional tax, imports, late penalties, and a GST invoice generator. Every calculator is built for the New Zealand tax system and checked against published Inland Revenue (IRD) rates and formulas.
We are not Inland Revenue. We are not a tax agent. We publish free tools so you can work out the numbers before you file in myIR or talk to your accountant.
Who runs this site
GSTCalc.nz is run by a small New Zealand product team. We write the calculators, keep the rates current, and fix bugs. We do not invent named “in house CPAs” or anonymous editorial boards.
When a page says “last verified”, that means we rechecked the numbers against the IRD page or guide linked on that page. If you find an error, email us. We will correct it and note the date.
How we keep numbers accurate
- GST uses the IRD 3/23 fraction from the GST guide (IR375).
- PAYE, ACC, KiwiSaver, and Student Loan figures follow the published rates for the current tax year (1 April to 31 March).
- Registration thresholds, filing frequencies, and taxable supply information rules follow ird.govt.nz/gst and the Goods and Services Tax Act 1985.
- When IRD publishes a rate or rule change, we update the affected calculator and the “last verified” date on that page.
Worked examples on the tools match IRD published maths where IRD publishes them. Rounding is to the nearest cent.
Privacy
Calculator inputs run in your browser. We do not upload your invoice amounts, salaries, or client names to our servers for the calculation itself. History and PDF export use your device (and browser storage where you save a business name). See the privacy policy for cookies and advertising.
How the site is funded
The tools are free. No account and no paywall. The site shows advertising. That pays for hosting and upkeep. We do not sell your calculation data.
What we are not
GSTCalc.nz is not tax advice, legal advice, or an IRD service. Complex situations (property, groups, disputes, multi entity structures) need a registered tax agent. Always confirm final figures before you file.
Contact
Calculation error, broken page, or a tool you need next: email contact@gstcalc.nz or use the contact page.