Methodology
How this calculator works
To add GST, multiply the exclusive price by 15% and add it. To extract GST from an inclusive total, divide by 1.15; the GST component is also 3/23 of that inclusive total.
Formula and sources reviewed2026/27 settingsReviewed 24 October 2026
🇳🇿 New Zealand GST Calculator
Add 15% GST to a price or extract the GST already included in a New Zealand total.
Advanced GST invoice calculation
NZ$
More options: invoice fees, discount and rounding+
Invoice result
Discounted line amount$0.00
GST-taxable amount$0.00
GST at 15%$0.00
Non-taxable fee$0.00
Rounding adjustment$0.00
Quantity / discount1 / 0.0%
Final invoice total$0.00
Worked example
Reading the result
NZ$100 excluding GST becomes NZ$115 including GST. In reverse, NZ$115 inclusive contains NZ$15 GST—not NZ$17.25—because the 15% is based on the NZ$100 pre-tax price.
Common questions
Frequently asked questions
How do I remove 15% GST?+
Divide the GST-inclusive total by 1.15. Subtracting 15% from the total gives the wrong base amount.
What fraction of a GST-inclusive price is GST?+
At New Zealand’s 15% rate, the GST component is 3/23 of the inclusive price.
Does every New Zealand sale include GST?+
No. Registration status and the type of supply matter. Check Inland Revenue guidance for zero-rated and exempt supplies.
Sources and review
Primary reference: Inland Revenue New Zealand — GST. Rules reviewed 24 October 2026.
Rule period: Current published rules within the page’s stated period and scope
Next scheduled review: 15 December 2026
The implemented rates, thresholds, displayed scope and representative boundary behaviour were reviewed against the primary source linked on the page.
Important scope
This arithmetic tool does not determine whether a sale is taxable, zero-rated or exempt, or whether a business can claim input tax. This calculator provides a planning estimate, not personal financial or tax advice.