Last updated: April 26, 2025 • IRD GST Guide
NZ GST Calculator — Add or Remove GST in Seconds
Enter any amount below. We’ll instantly calculate 15% GST, showing the GST component, exclusive price, and inclusive price using IRD-approved formulas. Change the rate for historical (12.5%) or what-if scenarios.
How to Calculate GST Manually
| Task | Quick Formula | Example (input $100 excl. GST) |
|---|---|---|
| Add GST | Amount × 1.15 | $100 × 1.15 = $115 |
| Extract GST Amount | Inclusive × 3 ÷ 23 | $115 × 3 ÷ 23 = $15 |
| Find Exclusive Price | Inclusive ÷ 1.15 | $115 ÷ 1.15 = $100 |
Why 3 ÷ 23? It’s the Inland Revenue shortcut for 15% GST that avoids rounding errors.
Zero-Rated vs Exempt Supplies
| Category | GST Status | Typical Examples |
|---|---|---|
| Exports | 0% (Zero-rated) | Goods shipped offshore, certain services to non-residents |
| Financial Services | Exempt | Bank fees, interest, loans (most) |
| Residential Rent | Exempt | Long-term housing leases |
| Certain Land Sales | 0% (Zero-rated) | Going-concern property deals between registered parties |
See the IRD guide on charging GST for full details.
GST Registration & Filing Snapshot
Register when turnover > $60,000 in 12 months (or expected)
Filing cycles: Monthly • Two-monthly (default) • Six-monthly
Payment due: 28th of month after period end (most common)
Keep taxable supply info (formerly tax invoices) for claims
FAQs
What is GST?
Goods & Services Tax, a 15% value-added tax on most NZ goods and services.
Is GST always 15%?
Yes, the standard rate has been 15% since 1 Oct 2010. Use the custom rate field for historical calculations (e.g., 12.5% pre-2010).
How do I add 15% GST?
Multiply the price excluding GST by 1.15. Or simply enter the exclusive amount into this calculator.
How do I remove GST from a price?
Divide the price including GST by 1.15, or multiply the inclusive price by 3 and then divide by 23. This calculator does it instantly.
Can I claim GST on overseas purchases?
Generally, only if NZ GST was charged at the border (by Customs) and you are GST-registered for business purposes.
When must I register for GST?
Compulsory registration is required if your turnover from taxable activities exceeded $60,000 in the last 12 months or is expected to in the next 12 months. You can also register voluntarily below this threshold.
Which items are GST-free?
Common examples include residential rent, most financial services (exempt), and exported goods/services (zero-rated).
Why can’t I just subtract 15% to find the pre-GST price?
Because GST (15%) is calculated on the *original* price before tax. Subtracting 15% from the *final* price will give you the wrong (too high) pre-GST amount.
Can I change the GST rate in the calculator?
Yes, simply edit the value in the “GST Rate (%)” field above the results.
Is this an official IRD tool?
No. KiwiMate is an independent tool designed to accurately reflect official IRD GST calculation methods for convenience.
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