GST Calculator New Zealand, 100% Free.
Add or remove 15% GST in seconds. Built for Kiwi sole traders, contractors, and small business owners who need the correct number fast.
Calculation history & PDF report
How to Calculate GST in New Zealand (Add or Remove)
The current Goods and Services Tax rate in New Zealand stands at a flat 15 percent today. To add this tax to a price that currently excludes it, you simply multiply your original figure by 1.15 directly. This calculation instantly provides you with the final total, inclusive of the required government tax amount every time.
When you need to remove the tax from a fully inclusive amount, you will use division instead. Divide the final total by 1.15 to reveal the original exclusive price accurately. To find only the tax portion, simply multiply your inclusive number by three before dividing that exact figure by 23 for a perfect result today.
How to Work Out GST on an Invoice
When creating a standard invoice, you must clearly display the tax components. Start by listing the subtotal of all items before any tax is applied. Then, multiply this subtotal by 0.15 to calculate the exact tax amount. This specific figure must be listed on its own separate line for clear accounting purposes and legal transparency.
After determining both the exclusive subtotal and the distinct tax value, simply add those two numbers together. This final sum represents the total amount your client needs to pay. Always review your final math carefully to ensure both the individual tax line and the final inclusive total match the correct legal percentages without rounding errors.
How to Check if GST is Correct
Verifying an existing tax charge is straightforward if you know the exact formula. Take the final inclusive total shown on the receipt and divide it by 1.15. This step reveals the base price of the goods. Next, subtract this base price from the final total to find the exact tax amount that was actually charged.
Once you have extracted the tax figure using this method, compare it to the tax amount printed on the document. If the two numbers match perfectly, the calculation is correct. If they differ by more than a few cents due to standard rounding, the issuer has made a mathematical error that requires immediate correction today.
More than a basic calculator
Two features you won't find on any other free NZ GST tool.
PDF export
Download a branded, itemised PDF for any calculation or a full batch. Send it to a client, file it for your accountant, or attach it to your IRD records.
Unique to GSTCalc.nzCalculation history
Every calculation you run is saved automatically — no account required. Review, delete, or export your log at any time. Perfect for batch GST return preparation.
Unique to GSTCalc.nzThe 3/23 method — explained
Not sure why the IRD uses 3/23 to extract GST? Our plain-English explainer covers the formula, the rounding rules, and why it matters for your GST return.
Three steps from invoice to record
Enter your amount
Choose whether you're adding GST to a net price, removing it from a gross total, or finding the GST component only. Enter the dollar figure.
Save to history
Click "Save to history" to add the entry to your itemised log. Add as many entries as you need — each one records the type, net, GST, and total.
Export your PDF
Add your business name and a report reference, then download a professional PDF. Use it for your GST return, send it to your bookkeeper, or keep it for your records.
Who uses GSTCalc.nz every week
From self-employed tradespeople to busy bookkeepers — our tool adapts to how you actually work with GST.
Freelance designer — Auckland
Invoices $2,300 (incl. GST) for a branding project. Enters the inclusive amount, instantly sees $300 belongs to IRD and $2,000 is her net income. Exports a PDF for her two-monthly myIR filing.
Building contractor — Wellington
Receives a $46,000 supplier invoice and needs to verify the GST input tax credit before filing. Uses the "Remove GST" mode — $6,000 GST identified in seconds, correctly claimed back against output tax.
Shopify store owner — Christchurch
Imports goods at $5,750 (incl. GST) for resale. Needs to isolate the $750 GST component for her input tax credit. Adds multiple import entries to the history log and exports the batch as a PDF for her accountant.
Part-time bookkeeper — Hamilton
Processes 40+ invoices a week for three clients. Batch-enters each invoice into the history log, reviews the itemised summary for accuracy, then downloads a branded PDF report for each client. Saves 75 minutes per week versus spreadsheets.
New Zealand GST rates — 2025/2026 tax year
A complete breakdown of how New Zealand's 15% Goods and Services Tax applies across every supply category, with IRD-verified classifications and real-world NZ examples.
| Supply category | GST rate | IRD classification | Common NZ examples |
|---|---|---|---|
| Standard-rated goods | 15% | Taxable supply (s.8) | Electronics, clothing, furniture, building materials, tools |
| Professional services | 15% | Taxable supply (s.8) | Accounting, legal advice, IT consulting, tradesperson labour |
| Commercial property rent | 15% | Taxable supply (s.8) | Office leases, warehouse space, retail shops, commercial storage |
| Digital / remote services | 15% | Taxable supply (s.8) | Software subscriptions, streaming services, online courses sold in NZ |
| Exported goods | 0% | Zero-rated (s.11) | Goods shipped overseas — Australia, UK, USA, Pacific Islands |
| Exported services | 0% | Zero-rated (s.11A) | Software development for offshore clients, consulting for foreign firms |
| Going concern sales | 0% | Zero-rated (s.11(1)(mb)) | Selling an entire operating business to a GST-registered buyer |
| Residential rent | Exempt | Exempt supply (s.14) | Renting a house, flat, apartment, or boarding house room |
| Financial services | Exempt | Exempt supply (s.14) | Bank interest, insurance premiums, share trading, mortgage fees |
| Donated goods (charity) | Exempt | Exempt supply (s.14) | Goods and services donated to registered charities |
GST registration thresholds — New Zealand 2026
| Annual turnover | Registration | Filing frequency | Key rule |
|---|---|---|---|
| Under $60,000/year | Voluntary | 6-monthly (if registered) | You may register voluntarily to claim input tax credits on business purchases |
| $60,000–$499,999/year | Mandatory | 2-monthly | Must register within 21 days of exceeding the $60,000 threshold in any 12-month period |
| $500,000–$23.9M/year | Mandatory | 2-monthly (monthly available) | May elect monthly filing; payments-basis accounting available under $2M turnover |
| $24M+/year | Mandatory | Monthly | Invoice-basis accounting required; monthly filing is compulsory |
Thresholds set under the Goods and Services Tax Act 1985 (s.51). The $60,000 threshold applies on a rolling 12-month basis — it does not reset each financial year. Once exceeded, registration is mandatory even if future turnover falls below $60,000.
How this calculator works: the official IRD 3/23 fraction method
Understanding the mathematics behind every calculation — and why it produces a different result to simply dividing by 1.15 at large volumes.
When you enter a GST-inclusive amount, our calculator applies the 3/23 fraction — the mathematically equivalent method prescribed by the IRD for extracting the GST component from any tax-inclusive price. Here's the logic:
Step 2: Tax fraction = 15 ÷ 115
Step 3: Tax fraction = 3 ÷ 23 = 0.13043478...
Example: Invoice total (incl. GST) = $1,150.00
GST component = $1,150.00 × 3/23 = $150.00
Net amount = $1,150.00 − $150.00 = $1,000.00
This fraction is important for businesses processing high invoice volumes. Simply dividing by 1.15 can introduce floating-point rounding errors that compound over hundreds of transactions. The 3/23 method avoids this — and it's what the IRD uses internally when auditing GST returns.
Rounding rules
Per the IRD's official guidance on calculating GST, amounts must be rounded to the nearest cent — if the third decimal is 5 or above, round up. Our calculator applies this automatically on every entry. For a business processing 200 invoices a month, even a 1-cent rounding discrepancy per transaction adds up to $24+ per year in filing differences. Our tool eliminates this entirely.
Five GST mistakes that cost Kiwi businesses thousands
Based on common errors identified in IRD audits. Each one has a real financial impact our calculator is designed to help you avoid.
1. Spending the GST you've collected
The most common — and most expensive — mistake for new business owners. When you invoice $1,150 for a $1,000 job, $150 belongs to the IRD, not you. Treating the full amount as revenue and spending it means you'll owe money at filing time that no longer exists. Our itemised history clearly separates the GST portion from net income on every entry, so you always know exactly how much to set aside.
Potential impact: $3,000–$15,000+ shortfall per year2. Claiming GST on exempt supplies
Not all business purchases carry a GST input tax credit. Common errors include claiming GST on residential rent paid for a home office, bank fees, insurance premiums, or personal expenses mixed with business use. If the supply is exempt under s.14 of the GST Act, there is no GST to reclaim — an incorrect claim triggers audit flags and a 20% shortfall penalty.
Penalty: 20% shortfall penalty + use-of-money interest at IRD rates3. Missing the $60,000 registration deadline
You must register for GST within 21 working days of your taxable supplies exceeding $60,000 in any rolling 12-month period. Many sole traders miss this because they track revenue by financial year. Late registration means you owe GST on all taxable sales made from the date you should have registered — retrospectively — with penalties and interest on top.
Risk: backdated GST liability + late registration fine4. Claiming without a valid tax invoice
To claim an input tax credit on purchases over $50, the supplier's invoice must include their GST registration number. For purchases over $1,000, the invoice must also include your name and address and the words "Tax Invoice." Claiming without a valid tax invoice is the single most common reason the IRD disallows input tax deductions during audits — and it's entirely avoidable.
Risk: entire input credit disallowed per invalid invoice5. Ignoring change-of-use adjustment rules
If you buy an asset for business use and later convert it partially to personal use — or vice versa — you must make a change-of-use adjustment on your GST return. For example, a vehicle purchased for 100% business use but later used 40% personally requires repayment of 40% of the GST originally claimed. A shift of more than 10% triggers mandatory adjustment. Failure to adjust is a frequent audit trigger for tradespeople, consultants, and property investors.
Risk: proportional GST repayment + potential penaltiesOur three-step verification process
Transparency about how we build, test, and maintain every calculation on this site.
Every calculation on GSTCalc.nz goes through three verification steps before going live:
Legislative cross-check
All tax logic is verified against the GST Act 1985 and current IRD Tax Information Bulletins. Updated within 4 hours of any legislative change.
Expert review
Content and calculations are reviewed by Sarah Reid, CPA — a qualified NZ tax professional and member of Chartered Accountants ANZ. Credentials verified on our About page.
Automated testing
50+ automated unit tests run on every update, comparing outputs against IRD-published worked examples. Edge cases — zero values, very large amounts, rounding boundaries — are all validated.
What we are: A precision calculation tool built by engineers and verified by NZ tax professionals. We provide mathematically correct GST figures for your invoices and returns.
What we are not: A substitute for professional tax advice. For complex situations — multi-entity structures, IRD disputes, property transactions — consult a registered tax agent. If you find an error in any calculation, email contact@gstcalc.nz immediately.
Frequently asked questions about GST in New Zealand
Plain-English answers to the questions Kiwi business owners ask most — verified against current IRD guidance.
The standard New Zealand GST rate is 15%, effective since 1 October 2010 when it was raised from 12.5%. This rate applies to most goods and services in NZ. Some supplies are zero-rated at 0% (such as exports), and some are fully exempt (such as residential rent and financial services). There are no proposed changes to the 15% rate for the 2026/27 tax year.
To add GST to a net price: multiply by 1.15 (e.g. $500 × 1.15 = $575). To remove GST from an inclusive price: divide by 1.15 (e.g. $575 ÷ 1.15 = $500). To find the GST portion in an inclusive price: multiply by 3/23 (e.g. $575 × 3/23 = $75). Our calculator automates all three methods — just enter your amount and select the calculation type.
You must register for GST when your taxable supplies exceed $60,000 in any 12-month period, or when you reasonably expect to exceed $60,000 in the next 12 months. Registration must be completed within 21 working days of exceeding the threshold. You may voluntarily register below $60,000 — this allows you to claim back input tax credits on GST-registered business purchases, which is often worthwhile if you have significant business expenses. Read our full $60,000 threshold guide.
Zero-rated (0% GST): You don't charge GST on the sale price, but you can still claim input tax credits on related purchases. Common examples: exported goods and services, the sale of a going concern business. Exempt: You don't charge GST, and you cannot claim input tax credits on related purchases. Common examples: residential rent, financial services, donated goods. The distinction is critical — claiming input credits on exempt activities is an audit risk.
Yes, but only on the business-use percentage. If you purchase a vehicle for $34,500 (incl. GST) and use it 70% for business, you can claim: $34,500 × 3/23 × 70% = $3,150 input tax credit. You must keep a logbook for the first 90 days to establish the business-use percentage, and this apportionment must be reviewed at least annually. If the ratio shifts by more than 10%, a change-of-use adjustment is required on your next GST return.
Both methods produce the same result mathematically. The IRD prescribes the 3/23 fraction specifically because it avoids floating-point rounding errors that can accumulate when processing large volumes of transactions in software. Our calculator uses 3/23 internally to match the IRD's own calculation method and ensure your figures pass audit scrutiny without rounding discrepancies.
Filing frequency depends on your annual taxable supplies. Most small businesses with turnover under $500,000 file 2-monthly returns, with payments due on the 28th of the month following each period. Businesses with turnover under $500,000 may elect to file 6-monthly. Businesses over $24M must file monthly. Your filing frequency is set when you register and can be changed with IRD approval. All returns are filed via myIR.
100% free — no account, no subscription, no usage limits. Every feature including the branded PDF export, batch history, and all three calculation modes is available to everyone at no cost. We generate revenue through contextual advertising, not by charging for the tool. We believe essential tax compliance tools should be accessible to every Kiwi business owner, regardless of size.
The PDF is designed as a working document for your own records and for sharing with your bookkeeper or accountant. It is not a substitute for lodging your return through myIR. However, the itemised breakdown is formatted to align with the figures you'll enter on your GST101A form, making preparation significantly faster. Many bookkeepers attach our PDF reports as supporting documentation during IRD audits.
GST applies to all goods imported into NZ regardless of value (since December 2019). For goods over $1,000, NZ Customs collects GST at the border: GST = (Customs value + Freight + Insurance + Customs duty) × 15%. For goods under $1,000, overseas sellers must collect GST at the point of sale. If you're GST-registered and the goods are for business use, you can claim this as an input tax credit. Use our dedicated import GST calculator for a full breakdown including customs duty estimation.
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GST Calculation Report
Official tax compliance summary · New Zealand · GSTCalc.nz
This report was generated by gstcalc.nz — New Zealand's free GST calculator, verified by qualified NZ tax professionals.
All calculations use the standard 15% GST rate and the official IRD 3/23 fraction method. Amounts rounded to the nearest cent per IRD guidelines.
Disclaimer: This document is provided for informational and record-keeping purposes only. It does not constitute financial or tax advice. Verify figures with a qualified accountant or registered tax agent before filing.
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