Free tool
NZ GST Calculator
Add 15% GST to a price, or work backwards from a GST-inclusive total. Built for tradies pricing jobs — no signup needed.
$
- Excluding GST
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- GST (15%)
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- Including GST
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The formulas (for doing it on paper)
| Add GST to a price | price × 1.15 | $400 × 1.15 = $460 |
| GST portion of a total | total × 3 ÷ 23 | $460 × 3 ÷ 23 = $60 |
| Remove GST from a total | total ÷ 1.15 | $460 ÷ 1.15 = $400 |
The common mistake: taking 15% offa GST-inclusive total. GST is 15% of the smaller (exclusive) number, so it is 13.04% of the total — that's why the backwards formula is ×3÷23, not ×0.15.
Common questions
- What is the GST rate in New Zealand?
- GST in New Zealand is 15%. It has been 15% since 1 October 2010 (it was 12.5% before that).
- How do I add GST to a price?
- Multiply the GST-exclusive price by 1.15. For example, $400 + GST is $400 × 1.15 = $460.
- How do I work out GST backwards from a total?
- To find the GST inside a GST-inclusive price, multiply the total by 3 and divide by 23. For example, $460 × 3 ÷ 23 = $60 of GST, leaving $400 excluding GST. Dividing the total by 1.15 gives the GST-exclusive amount directly.
- Do I have to charge GST?
- You must register for GST (and charge it) once your turnover is over $60,000 in any 12-month period, or if you add GST to your prices. Below that threshold registration is optional — many sole-trader tradies register anyway to claim GST back on tools and materials.
- Should my quotes show prices including or excluding GST?
- For consumers, showing GST-inclusive totals is the safest practice under the Fair Trading Act — hidden extras cause disputes. For commercial clients, plus-GST pricing is common. Either way, say clearly which one your quote is.