How do I work out GST in NZ?
To find the GST in a price, multiply by 3 and divide by 23. Add GST, check registration and see when your return is due.
What this guide covers
To find the goods and services tax (GST) inside a price, multiply by 3, then divide by 23. To add GST, multiply by 1.15.
The two sums
In New Zealand, GST is 15% on most taxable sales. A registered business collects it for Inland Revenue (IRD).
Take GST out of a price that includes it:
Price × 3 ÷ 23 = the GST
Price − the GST = the price before GST
Add GST to a price that does not include it:
Price × 0.15 = the GST
Price × 1.15 = the price with GST
Why 3 and 23? GST is 15 on top of every 100. So in every $115 you take, $15 is GST. That is 3 parts in every 23.
Worked example: a cafe's GST return
A small cafe files a GST return every 2 months. This example covers September and October 2026. All sales and eligible costs have 15% GST. The cafe uses the payments basis and all amounts were paid in this period.
Sales, including GST:
Takings: $46,000
GST in that: $46,000 × 3 ÷ 23 = $6,000
Costs it can claim, including GST:
Stock, rent and power with GST on the bill: $17,250
GST in that: $17,250 × 3 ÷ 23 = $2,250
What it owes IRD:
$6,000 − $2,250 = $3,750
Due: 30 November 2026, because 28 November falls on a Saturday
So $3,750 of the money in the bank on 31 October was never the cafe's to spend.
Which costs can I claim?
Only include eligible costs used in your taxable activity. Keep the required taxable supply records. Use only the business share of mixed-use costs. Do not include wages, private costs or costs without claimable GST. IRD IR135, page 12, says GST cannot be claimed on salary or wages.
Use the same accounting basis as your return.
Payments basis: include money received and paid.
Invoice basis: include invoiced sales, or the full sale when any payment arrives first. Include eligible purchases invoiced or paid, with records.
Hybrid basis: use invoice basis for sales, and payments basis for costs.
This simple estimate excludes zero-rated sales, exempt sales, special supplies and adjustments. Use myIR or your accountant for those.
The common mistake: taking 15% off
Taking 15% off a GST price gives the wrong answer. It takes off too much.
An invoice is $230, including GST.
15% of $230 is $34.50. That is wrong.
$230 × 3 ÷ 23 is $30. That is the GST.
The price before GST is $200.
The 15% goes on the price before GST. So you can only take it back off with 3 ÷ 23.
Do I have to register for GST?
You must register if your turnover reaches $60,000 in 12 months. IRD looks two ways:
Looking back: your sales in the last 12 months were $60,000 or more.
Looking ahead: you expect $60,000 or more in the next 12 months.
Turnover is the money you make from selling goods or services. It is your sales, not your profit.
Worked example: an electrician
Bills: $4,800 a month
A year: $4,800 × 12 = $57,600. Under the line.
A new $5,000 job comes in.
Next 12 months: $57,600 + $5,000 = $62,600
That is over $60,000, so it is time to register.
Already charging GST? You must register if you add GST to prices for your taxable activity, even below $60,000.
Under $60,000? You can choose to register. You then add GST to your prices and file returns. If most of your customers are businesses that claim GST back, ask your accountant whether it suits you.
When is my GST return due?
The 28th of the month after your period ends. There are 2 exceptions. If a due date falls on a weekend or public holiday, it moves to the next working day:
Period ending 31 March: due 7 May.
Period ending 30 November: due 15 January.
You cannot get more time to file. Late filing penalties may apply:
$50 if you count GST when you are paid (the payments basis)
$250 on the invoice or hybrid basis
How often you file depends on your sales in any 12 months:
Every 6 months: sales under $500,000
Every 2 months: sales under $24 million
Every month: anyone can. You must if sales are over $24 million.
Getting the date or the amount wrong costs real money. If you are not sure, check with IRD or your accountant.
What good looks like
GST sits in its own account. Move the GST out of each payment as it comes in.
The return is filed by its due date. Check weekend and public holiday shifts in myIR.
The GST owed is no surprise. You know the figure before the return is due.
Do this week
Open a second bank account for GST. Your banking app may let you add one in a few minutes.
Move 3/23 of last week's takings into it. On $8,000 of takings, that is $1,043, rounded to whole dollars.
Write your next due date where you will see it. Check it against the list above.
Common mistakes
Taking 15% off a GST price. Use × 3 ÷ 23 instead.
Spending the GST. It sits in your bank, but it belongs to IRD.
Forgetting the 2 odd dates. The return for the period ending 30 November is due 15 January. The one for 31 March is due 7 May.
Testing profit, not sales. The $60,000 line is your turnover, not what you keep.
More help — links checked 4 November 2026
Free IRD GST worksheets: Sort sales and eligible costs before filing; the IR375 guide includes return worksheets. https://www.ird.govt.nz/-/media/project/ir/home/documents/forms-and-guides/ir300---ir399/ir375/ir375.pdf
Watch: GST in New Zealand Explained (2026): DFKORB360, 58 seconds, 18 May 2026: a quick NZ introduction to 15% GST and filing duties; captions checked against IRD. https://www.youtube.com/watch?v=nCR706iP49Q
Official IRD tools: myIR does return calculations; IRD also has an accounting-basis chooser and a taxable-supply records tool. https://www.ird.govt.nz/gst/filing-and-paying-gst-and-refunds/calculating-gst
Get help: a Regional Business Partner advisor: NZ$0 for a business assessment; helps you find local support, rather than completing a GST return. https://business-south.org.nz/how-we-help/regional-business-partners/
Ask an AI assistant: Copy the prompt below for a draft check; verify dates, costs and rules against the linked IRD pages.
AI prompt
Help me estimate New Zealand GST at 15%. My period ends [month/year]. My accounting basis is [payments/invoice/hybrid]. Sales including GST: $[amount]. Eligible business costs including claimable GST: $[amount]. Show GST on sales, claimable GST on costs, and the difference. Check the due date against current IRD key dates, including weekends and public holidays. Ask which figures or records are missing. Flag mixed use, zero-rated or exempt sales, and adjustments. Link official IRD sources. Do not assume this is a completed return.
Official tools
IRD accounting-basis chooser: https://www.ird.govt.nz/gst/registering-for-gst/which-gst-accounting-basis-and-filing-frequency-should-i-use
IRD records tool: https://www.ird.govt.nz/gst/taxable-supply-information-for-gst
The steps
Open a separate bank account for GST.
Move 3/23 of GST-inclusive takings into it. On $8,000, that is $1,043 rounded to whole dollars.
Check your next return date in myIR.
Sources — checked 4 November 2026
Work out your GST free: /tools/gst-calculator
Price with GST: GP calculator: /tools/gp-calculator
Find your cash gap: /guides/profitable-but-no-cash-small-business-nz
IRD, Charging GST — checked 4 Nov 2026: https://www.ird.govt.nz/gst/charging-gst
IRD, Registering for GST — checked 4 Nov 2026: https://www.ird.govt.nz/gst/registering-for-gst
IRD, Registering for GST voluntarily — checked 4 Nov 2026: https://www.ird.govt.nz/gst/registering-for-gst/registering-for-gst-voluntarily
IRD, Filing and paying GST — checked 4 Nov 2026: https://www.ird.govt.nz/gst/filing-and-paying-gst-and-refunds
IRD, Which GST accounting basis and filing frequency should I use — checked 4 Nov 2026: https://www.ird.govt.nz/gst/registering-for-gst/which-gst-accounting-basis-and-filing-frequency-should-i-use
IRD, Late filing penalties — checked 4 Nov 2026: https://www.ird.govt.nz/managing-my-tax/penalties-and-interest/penalties-and-debt/late-filing-penalties
IRD: eligible costs — checked 4 Nov 2026: https://www.ird.govt.nz/gst/claiming-gst
IRD IR135: wages, page 12 — checked 4 Nov 2026: https://www.ird.govt.nz/-/media/project/ir/home/documents/forms-and-guides/ir100---ir199/ir135/ir135.pdf
IRD: register in myIR — checked 4 Nov 2026: https://www.ird.govt.nz/gst/registering-for-gst/register-for-gst
IRD: key dates — checked 4 Nov 2026: https://www.ird.govt.nz/key-dates
These are general examples, not tax advice. Check your own figures with your accountant or IRD. Read our disclaimer: /disclaimer
Is the $60,000 my profit or my sales?
Your sales. IRD calls it turnover: the money you make from selling goods or services. Profit is what is left after costs.
What if I go over $60,000 without meaning to?
Register as soon as you see it coming. IRD can backdate your start date in rare cases. Talk to IRD or your accountant before you send invoices without GST.
Is the GST in my bank account my money?
No. You owe it to IRD, less claimable GST on eligible business costs. Keep it apart so you can pay the return.
How do I take GST off a price?
Multiply the price by 3, then divide by 23. That is the GST. Take it off to get the price before GST.
When is GST due in NZ?
On the 28th of the month after your period ends. The exceptions are 15 January and 7 May. Weekend or public holiday dates move to the next working day. Weekend or public holiday dates move to the next working day.