New Zealand Online GST calculator
Use this New Zealand GST calculator to add 15% GST to a price, remove GST from a GST-inclusive amount, or identify the GST component of an inclusive price.
New Zealand GST Calculator
Enter an amount and choose the calculation you need.
New Zealand GST formulas
Adding GST to a GST-exclusive amount
For a standard 15% GST calculation:
GST = amount × 0.15
Total including GST = amount × 1.15
Removing GST from a GST-inclusive amount
If the amount already includes 15% GST:
Amount before GST = inclusive amount ÷ 1.15
GST = inclusive amount − amount before GST
Finding the GST component of an inclusive price
For a New Zealand GST-inclusive amount, the GST component is:
GST = inclusive amount × 3 ÷ 23
For example, GST included in $115 is $15, and the amount before GST is $100.
What this calculator does
- Adds standard 15% New Zealand GST to an amount.
- Removes standard 15% GST from an inclusive amount.
- Calculates the GST component contained in an inclusive amount.
- Shows the formulas so the arithmetic can be checked manually.
What this calculator does not determine
This is a basic arithmetic calculator. It does not determine whether a transaction is taxable, exempt, zero-rated, deductible, refundable, or subject to special GST rules. It also does not prepare GST returns, calculate a tax refund, determine GST registration requirements, or provide transaction-specific tax advice.
When to check official guidance
GST treatment can depend on the type of supply, the parties involved, the accounting basis, and other facts. For current New Zealand GST rules and filing requirements, check Inland Revenue (IRD).
Examples
| Scenario | Calculation | Result |
|---|---|---|
| $100 before GST | $100 × 15% | $15 GST; $115 total |
| $115 including GST | $115 ÷ 1.15 | $100 before GST; $15 GST |
| $230 including GST | $230 × 3 ÷ 23 | $30 GST; $200 before GST |
Important note
The calculator uses standard 15% GST arithmetic. Always check the current IRD guidance when the transaction involves a special GST treatment or when the result will be used for an official filing or business decision.
More New Zealand GST tools
Need more than a basic GST calculation? Use the NZ GST Registration Threshold Calculator to screen the standard NZ$60,000 threshold, or the NZ GST Return Calculator for a simple arithmetic estimate of GST collected and entered purchase GST. For formulas, see our NZ GST formula guide.
