NZ GST Calculator – Add and Remove GST

GST catches people out in two very specific moments: working out what to actually charge a customer, and working out how much of a price you've already been charged is tax versus the real cost of the thing. This calculator handles both directions at once, add GST to a price, or pull the GST component back out of one, at New Zealand's current 15% rate.

How to use this calculator

Pick the tab that matches what you actually have in front of you:

• Add GST, if you have a GST-exclusive price (what something costs before tax) and need to know what to charge including GST.
• Remove GST, if you have a GST-inclusive price (what someone actually paid, or what's shown on a receipt) and need to split it into the GST portion and the real cost.

Both directions show you all three figures together: the exclusive amount, the GST amount, and the inclusive amount, so you're never left doing a second calculation to see the full picture.

The maths behind it

New Zealand's GST rate is 15%, which makes both directions straightforward once you know the two formulas.

Adding GST to a price

Multiply the exclusive amount by 1.15 to get the GST-inclusive price. Or, if you just want the GST component on its own, multiply the exclusive amount by 0.15.

Example: a $200 service, GST-exclusive. GST = $200 × 0.15 = $30. GST-inclusive price = $200 × 1.15 = $230.

Removing GST from a price

This is the one that trips people up, dividing by 1.15 and then subtracting isn't wrong, but there's a cleaner way that avoids a common rounding mistake: multiply the GST-inclusive amount directly by 3/23 to get the GST component. Subtracting 15% from the inclusive price does not give you the right exclusive amount, since 15% of the inclusive price is a larger dollar figure than 15% of the exclusive price was to begin with.

Example: a $230 GST-inclusive invoice. GST component = $230 × 3/23 = $30. Exclusive amount = $230 − $30 = $200.

The 3/23 figure comes directly from the 15% rate: 15/115 simplifies to 3/23. If the rate ever changes, this fraction would need to change with it, IRD publishes the current figure whenever the rate is updated.

A brief history of the GST rate

If you've come across an old spreadsheet, invoice template, or even a stray calculator online still working off 12.5%, that figure isn't wrong, it's just old. The rate has moved twice since GST first arrived: it started at 10% back in 1986, climbed to 12.5% a few years later in 1989, and has sat at 15% since 1 October 2010. Anything dated before that October 2010 change would legitimately have been calculated at the lower rate, but for current work, 15% is what applies.

When you need to register for GST

Not every business needs to charge GST. Registration becomes compulsory once your turnover exceeds $60,000 in any rolling 12-month period, this isn't tied to a calendar or financial year, it's a continuously moving 12-month window. The threshold applies whether you've already exceeded $60,000 looking backward, or you reasonably expect to exceed it looking forward, either test triggers the requirement to register.

You can also register voluntarily below $60,000. This is common for businesses whose customers are themselves GST-registered, since it lets you claim back GST on your own business expenses (input tax) even while your revenue is still below the compulsory threshold.

Once registered, you must charge GST on your taxable supplies from your registration date, and you'll need to file regular GST returns with Inland Revenue, generally due by the 28th of the month following the end of your filing period.

GST on imported goods

Buying from overseas adds a wrinkle that a lot of general GST guides skip over entirely. For goods valued at or under $1,000, GST is typically collected at the point of sale by the overseas retailer itself, larger offshore sellers with significant New Zealand sales are required to register for and collect GST directly, the same way a local business would. For goods valued over $1,000, GST (and any applicable customs duty) is instead collected by New Zealand Customs at the border, rather than by the seller.

This is why the GST you're charged on an overseas order sometimes shows up differently depending on the retailer and the value of what you're buying, it's not inconsistent, it's two different collection mechanisms depending on which side of the $1,000 line the purchase falls on.

Zero-rated vs exempt supplies

These two terms get used interchangeably, but they're not the same thing, and the distinction actually matters if you're GST-registered.

• Zero-rated supplies are taxable, just at a 0% rate, most commonly exported goods and services. Because they're still technically taxable supplies, a GST-registered business can claim back GST on related expenses (input tax) even though it charged no GST on the sale itself.
• Exempt supplies, such as most financial services and residential rent, aren't taxable supplies at all. A business making only exempt supplies generally can't claim back GST on its related expenses.

Understanding a GST return

If you're registered, each GST return comes down to one core calculation: the GST you've charged customers (output tax) minus the GST you've paid on business expenses (input tax). If output tax is higher, you pay the difference to IRD. If input tax is higher, for example after a large equipment purchase, you're due a refund instead.

Example: over a filing period, a business charges $8,000 in GST across its sales (output tax) and pays $3,200 in GST on its own purchases and expenses (input tax). GST payable = $8,000 − $3,200 = $4,800 owed to IRD for that period.

Frequently Asked Questions

What is the current GST rate in New Zealand?

15%, and it has been since 1 October 2010. Before that it was 12.5% (from 1989) and originally 10% when GST was introduced in 1986.

What formula removes GST from a total price?

Multiply the GST-inclusive amount by 3/23 to get the GST component. Subtract that from the inclusive amount to get the GST-exclusive price. Don't simply subtract 15% from the inclusive total, that produces an incorrect result because 15% of the inclusive amount is a larger figure than 15% of the exclusive amount was originally.

How do I calculate GST-exclusive from GST-inclusive?

Divide the GST-inclusive amount by 1.15, or equivalently, subtract the GST component (inclusive amount × 3/23) from the inclusive total. Both methods give the same result.

Do I need to charge GST if I'm not registered?

No. Only GST-registered businesses can charge GST. If your turnover is below the $60,000 threshold and you haven't voluntarily registered, you shouldn't be adding GST to your prices or invoices.

Is GST charged on imported goods bought online?

Yes, in most cases. For goods valued at $1,000 or under, the overseas seller typically collects GST at checkout. For goods over $1,000, GST and any customs duty are collected by New Zealand Customs when the goods arrive.

What's the difference between zero-rated and GST-exempt?

Zero-rated supplies (like most exports) are still technically taxable, just at 0%, which means a registered business can still claim back GST on related costs. Exempt supplies (like residential rent and most financial services) aren't taxable at all, and related input tax generally can't be claimed.

Is this calculator accurate for filing my GST return?

It's accurate for calculating GST on individual amounts, adding or removing GST from a price. A full GST return involves totalling output tax and input tax across every transaction in a filing period, which this tool doesn't do on its own. For return preparation, accounting software or a bookkeeper is the more appropriate tool.