GST Calculator NZ — Add or Remove 15% GST

Add 15% GST to a price, or take the GST out of a GST-inclusive total using Inland Revenue's ×3÷23 method — free, instant, and shown line by line.

AmountPrice excluding GST

Price excluding GST$100.00

GST (15%)$15.00

Price including GST $115.00

Standard rate: 15% since 1 October 2010 (Inland Revenue).

What this result means for you

The price excluding GST is $100.00, the 15% GST adds $15.00, and the GST-inclusive total is $115.00. To go back the other way later, multiply the total by 3 and divide by 23 — or switch this calculator to Remove.

Percentage trap: subtracting 15% from $115.00 gives $97.75 — off by $2.25 from the correct $100.00. Adding 15% and subtracting 15% are not opposites. Divide by 1.15, or use ×3÷23.

Includes your calculation, the NZ Magic Numbers (×1.15 and ×3÷23) and ready-to-paste Excel formulas. Pure client-side — no data leaves your browser.

Not in New Zealand? Use the multi-country GST Calculator →

Only need to work a total backwards? Use the Reverse GST Calculator →

How to Calculate NZ GST in 3 Steps

Enter your amount

Type the price excluding GST (Add mode) or the GST-inclusive total (Remove mode).

Pick add or remove

Add 15% GST to a quote or price, or pull the GST content out of a total using Inland Revenue's ×3÷23 method.

Read the result line by line

The price excluding GST, the GST amount and the GST-inclusive total appear instantly — copy them or download the CSV.

New Zealand's GST Rate: 15% Since 1 October 2010

New Zealand charges a single flat GST rate of 15% on most goods and services, including imports. There are no regional rates and no product tiers: one country, one rate. GST started at 10% on 1 October 1986, rose to 12.5% in 1989, and has been 15% since 1 October 2010 — with no change scheduled for the 2026/27 tax year. A few supplies sit outside the standard rate: exports are zero-rated at 0%, while residential rent, most financial services and donated goods are exempt. Businesses must register for GST once their turnover passes $60,000 in any rolling 12-month period — a threshold that has grown step by step from $24,000 in 1986. Some calculator pages online still demonstrate with other countries' rates or point readers to the wrong tax office; this page lists its official New Zealand sources and the date the rate was last verified.

×3÷23 or ÷1.15 — Which Formula Is Right?

Both. They give exactly the same answer, every time, for any amount. Inland Revenue's recommended way to find the GST inside a GST-inclusive price is to multiply by 3 and divide by 23. The other way is to divide the total by 1.15 to get the before-GST price, then subtract. The two are mathematically identical: taking a fraction 15/115 of the total and simplifying it (divide top and bottom by 5) leaves exactly 3/23 — the IRD fraction is not an approximation. So why does IRD prefer ×3÷23? It gets the GST in one step. The ÷1.15 route needs two steps, and carrying that middle number back into a second calculation is where typing mistakes creep in. Here is IRD's own example: a $115 pair of headphones contains $115 × 3 ÷ 23 = $15 of GST, so the price before GST was $115 − $15 = $100. This calculator uses the ×3÷23 method and shows you the working.

How This Calculator Works (the Formulas)

Add mode treats your amount as a price excluding GST: the GST is 15% of it (multiply by 0.15), and the total is the amount × 1.15. So $100 becomes $15 GST and a $115 total, $200 becomes $230, and $500 becomes $575. Remove mode treats your amount as a GST-inclusive total: the GST content is the amount × 3 ÷ 23 (Inland Revenue's method), and the price excluding GST is what's left after subtracting it — the same answer you would get dividing by 1.15. One warning before you reach for a shortcut: never subtract 15% to remove GST. $100 + 15% = $115, but $115 − 15% = $97.75, not $100. Percentages do not reverse by subtraction — divide, or use ×3÷23.

When to Use This Calculator — and When Not To

Use it for everyday New Zealand price work: turning a "$650 + GST" quote into the amount that will actually leave your bank account, adding GST to your own quotes and invoices, pulling the GST content out of a receipt or phone bill for your records, and checking supplier figures before you file. Tradespeople and contractors quote "plus GST" constantly — businesses can claim the GST back, so the before-GST price is the number that matters to them, and this calculator bridges the two views of the same price in one step. It is not the right tool for a few jobs: zero-rated supplies such as exports and going-concern business sales (GST is 0% there), exempt supplies such as residential rent and most financial services (no GST at all), and GST on imports — Customs uses a different formula that adds freight, insurance and duty to the value before applying 15%, so check Inland Revenue or NZ Customs for those. And if you need your net GST position for a return (GST collected minus GST paid), that is a job for your accounting records in myIR.

Common Mistakes with NZ GST

The classic: subtracting 15% to remove GST. $115 − 15% gives $97.75 instead of the correct $100 — wrong by $2.25 on every hundred dollars. A popular variation is "just knock off about 13%", which gets close but is never exact and quietly drifts as amounts grow; the only correct moves are ÷1.15 or ×3÷23. Second: treating the GST you collect as income. It is not your money — you are collecting it for Inland Revenue, and the cleanest habit (one experienced business owners repeat constantly) is to set the GST aside as it comes in and keep your books in GST-exclusive amounts. Third: misreading quotes. "$100 + GST" means $115 leaves your pocket if you cannot claim GST back — when comparing quotes as a consumer, multiply each one by 1.15 first so you compare what you will actually pay.

NZ GST Magic Numbers

One factor per task — multiply to add GST, divide or use the IRD fraction to take it out.

Task	Factor
Add 15% GST to a price	× 1.15
Price without GST from a total	÷ 1.15
GST content of a total (IRD method)	× 3 ÷ 23
GST on a GST-exclusive price	× 0.15

NZ GST Rate and Registration Threshold History

Every GST rate change since 1986, and how the compulsory registration threshold has grown — with official sources.

GST rate
1 Oct 1986 – 30 Jun 1989	10%
1 Jul 1989 – 30 Sep 2010	12.5%
Since 1 Oct 2010 Current	15%

Registration threshold (rolling 12-month turnover)
1 Oct 1986	$24,000
1 Oct 1990	$30,000
1 Oct 2000	$40,000
Since 1 Apr 2009 Current	$60,000

Sources: Inland Revenue – GST · Inland Revenue – Calculating your GST · Wikipedia – GST (New Zealand) — Rate last verified: 2026-06-11

NZ GST Calculator FAQ

Q1.What is the GST rate in New Zealand?

15%. The rate has applied since 1 October 2010, when it rose from 12.5%. GST started at 10% when it was introduced on 1 October 1986, and there is no change scheduled for the 2026/27 tax year. It is a single flat rate across the country, charged on most goods and services including imports. Source: Inland Revenue.

Q2.How do I add GST to a price in NZ?

Multiply the price by 1.15. A $500 quote becomes $500 × 1.15 = $575 including GST, and the GST component is $75. Equivalently, the GST alone is 15% of the price (multiply by 0.15) — Inland Revenue's own example adds $15 to a $100 price for a $115 total.

Q3.How do I work out the GST in a GST-inclusive price?

Use Inland Revenue's method: multiply the total by 3 and divide by 23. A $115 total contains $115 × 3 ÷ 23 = $15 of GST, so the price before GST was $100. The shortcut works for any amount — $230 contains $30 of GST, $575 contains $75.

Q4.Is ×3÷23 or ÷1.15 the correct way to remove GST?

Both are correct, and they always give the same answer — 3/23 is simply the fraction 15/115 simplified, so it is not an approximation. Inland Revenue recommends ×3÷23 because it produces the GST amount in one step; dividing by 1.15 first and then subtracting needs a second calculation, which is one more chance to mistype a number.

Q5.Why can't I just subtract 15% to remove GST?

Because the 15% was charged on the before-GST price, not on the total you are starting from. $100 + 15% = $115, but $115 − 15% takes away 15% of 115 — $17.25 instead of $15 — leaving $97.75. The error grows with the amount. Always divide by 1.15 or multiply by 3 and divide by 23.

Q6.When do I have to register for GST in New Zealand?

Registration is compulsory once your turnover passes $60,000 in any rolling 12-month period — the trigger is turnover, not profit, and you have 21 days from crossing the threshold to register with Inland Revenue. You can register voluntarily below that, which can make sense if your customers are mainly GST-registered businesses or your input costs are high.

Q7.What is the difference between zero-rated and exempt supplies?

Both mean no GST is charged on the sale, but the claim-back rules differ. Zero-rated supplies (exports, services performed overseas, the sale of a going concern) are taxed at 0%, and the supplier can still claim GST on related costs. Exempt supplies (residential rent, most financial services, donated goods sold by non-profits) sit outside GST entirely, and no input GST can be claimed on costs related to them.

Q8.Why do tradies and service companies quote prices "+ GST"?

Because most of their customers are businesses, and businesses claim the GST back — so the before-GST price is the real cost to them. Quoting "plus GST" also makes a price look smaller. As a consumer you cannot claim GST back, so multiply any "+ GST" quote by 1.15 to see what you will actually pay: $367 + GST is really $422.05.

Q9.Do I pay income tax on the GST I collect?

No. GST is not your income — you collect it on Inland Revenue's behalf and pass it on. Income tax is calculated on your GST-exclusive earnings: if you invoice $115,000 including GST, the $15,000 of GST goes to IRD and your income for tax purposes is $100,000. That is also why accountants keep business books in GST-exclusive amounts.

Q10.Do I pay GST on imports and overseas online purchases?

Usually yes. GST applies to most goods imported into New Zealand — for low-value goods, overseas sellers typically collect the 15% at checkout, while for higher-value shipments NZ Customs charges GST on the item's value plus freight, insurance and any duty, which is a different calculation from this page's. Check Inland Revenue or NZ Customs before relying on a number for an import.

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