NZ GST calculator: add or remove 15% GST
Enter an amount in NZ dollars and choose whether it already includes GST. You get the GST-exclusive amount, the GST and the GST-inclusive amount, rounded to the cent.
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How NZ GST is worked out
- The rate is 15% on most taxable supplies made by a GST-registered business.
- Adding GST: $100 plus GST = $115 (GST is 15% of the GST-exclusive price).
- Taking GST out (the 3/23 rule): the GST in a GST-inclusive price is 3/23 of it. IRD's example: $100 including GST contains $13.04 of GST.
- Common mistake: taking 15% off a GST-inclusive price. 15% of $115 is $17.25, but the GST in $115 is $15.00 (3/23 of $115).
| GST-exclusive | GST | GST-inclusive | |
|---|---|---|---|
| Quote $1,000 + GST | $1,000.00 | $150.00 | $1,150.00 |
| Receipt for $100 incl. GST | $86.96 | $100 × 3/23 = $13.04 | $100.00 |
Do you need to register?
You must register for GST if you carry on a taxable activity and your turnover was at least NZ$60,000 in the last 12 months, or you expect it to be at least NZ$60,000 in the next 12 months (any 12 consecutive months, not just the tax year). You can register voluntarily below that. Not every supply carries 15%: some are zero-rated (0%), some are exempt (for example residential rent and some financial services), and land sales have their own rules.
Sources (checked 17 Oct 2026): Inland Revenue Charging GST (15%, 3/23, the $100 → $13.04 example; zero-rated and exempt supplies); Registering for GST ($60,000 threshold); GST guide IR375.
General information, not tax advice. It doesn't take your circumstances into account. Check with Inland Revenue or a tax agent before relying on it.
Related
- Article: NZ GST return (GST101A) boxes 5 to 15 explained, with 2026-27 due dates
- Paid spreadsheet: NZ GST Workbook 2026-27 (adds up a whole period for your return) · NZ Invoice Chaser for n8n
- Australia instead? AU GST calculator (10%, ÷11)