How to add GST in New Zealand
Multiply the GST-exclusive price by 15% to find the GST amount, then add it to the starting price. For example, $100.00 plus $15.00 GST is $115.00 including GST.
Inclusive price = exclusive price × 1.15
New Zealand · Standard GST rate
GST calculator NZ
Add 15% GST to a GST-exclusive price or remove GST from an inclusive total. See the original price, exact GST component and final price together.
Last reviewed: 22 August 2026
Price including GST
$115.00
Calculated at the standard 15% NZ GST rate
- GST-exclusive amount
- $100.00
- GST component
- $15.00
- GST-inclusive amount
- $115.00
$100.00 + $15.00 GST = $115.00
Standard-rate arithmetic: This tool does not decide whether a transaction is taxable, zero-rated or exempt, or whether GST can be claimed.
How to remove GST from a price
Inland Revenue recommends multiplying the inclusive price by 3 and dividing by 23 to extract the GST component. For $115.00, the GST is $15.00 and the exclusive price is $100.00.
GST component = inclusive price × 3 ÷ 23
GST-inclusive and GST-exclusive examples
These examples use the standard 15% rate and round displayed currency to cents.
| Exclusive | GST | Inclusive |
|---|---|---|
| $25.00 | $3.75 | $28.75 |
| $100.00 | $15.00 | $115.00 |
| $500.00 | $75.00 | $575.00 |
| $1,000.00 | $150.00 | $1,150.00 |
Why removing 15% is different
GST is 15% of the exclusive amount. Once it has been added, the GST component is 3/23 of the larger inclusive total—about 13.04%—so simply subtracting 15% gives the wrong result.
When the standard rate may not apply
Some New Zealand supplies are zero-rated or exempt, and special rules can apply to areas such as land, exports, financial services and mixed business/private use.
Invoices and rounding
This calculator retains full precision and displays cents. A real invoice or accounting system may round individual line items, which can create a small difference from calculating GST once on a combined total.
GST registration matters
Only GST-registered businesses can generally charge GST or claim GST on purchases. This arithmetic tool does not determine registration, filing or entitlement.
Official GST sources
The standard rate and formulas are checked against Inland Revenue guidance. Confirm transaction-specific treatment with IRD or a qualified adviser.
Frequently asked questions
What is the GST rate in New Zealand?
The standard New Zealand GST rate is 15%. Some supplies can be zero-rated, exempt or covered by special rules, so the standard rate does not apply to every transaction.
How do I add GST to a price?
Multiply the GST-exclusive amount by 15% to find the GST component, then add that component to the original amount. Equivalently, multiply the exclusive amount by 1.15.
How do I remove GST from an inclusive price?
Multiply the GST-inclusive amount by 3 and divide by 23 to find the GST component. Subtract that component from the inclusive total to find the exclusive amount.
Why do I not subtract 15% to remove GST?
The 15% was calculated from the smaller GST-exclusive price, not from the larger inclusive total. GST is 3/23 of a standard-rated GST-inclusive amount.
Can I use this result for a GST return?
This tool performs the standard-rate arithmetic only. GST returns can involve accounting bases, adjustments, zero-rated or exempt supplies, mixed use and record requirements, so confirm filing treatment with Inland Revenue or an adviser.
Does the calculator round GST?
The formulas retain full numeric precision and the interface displays currency to the nearest cent. Invoice totals or accounting software may apply rounding across line items differently.