How to calculate GST in New Zealand
GST in New Zealand is 15%. There are only two sums you'll ever need.
Adding GST to a price
Multiply the price excluding GST by 1.15.
$200 × 1.15 = $230. The GST part is $200 × 0.15 = $30.
Removing GST from a price
Divide the GST-inclusive price by 1.15 to get the price without GST. To get just the GST, multiply by 3 and divide by 23.
$230 ÷ 1.15 = $200, and $230 × 3 ÷ 23 = $30.
A common mistake is taking 15% off the inclusive price. 15% of $230 is $34.50, which is too much, because the GST was 15% of the exclusive price, not the total. The 3/23 fraction fixes that.
Quick reference
| Excl. GST | GST (15%) | Incl. GST |
|---|
Questions people ask
What is the GST rate in New Zealand?
15%. It applies to most goods and services sold in New Zealand by GST-registered businesses. Some supplies are zero-rated (0%), such as most exports, and some are exempt, such as residential rent and financial services.
Do I have to register for GST?
You must register if your turnover was more than $60,000 in the last 12 months, or you expect it to go over $60,000 in the next 12. Below that, registering is optional. Inland Revenue has the full rules (link below).
Should my prices show GST?
If you sell to the public, show GST-inclusive prices, since that's what people actually pay. Business-to-business quotes are often given excluding GST, but say so clearly ("+ GST") so nobody is surprised.
Why does 3/23 work?
An inclusive price is 115 parts, and 15 of those parts are GST. 15/115 simplifies to 3/23, so the GST inside any inclusive amount is that amount × 3 ÷ 23.
Does this calculator store what I type?
No. Everything is calculated in your browser, and nothing you type is sent anywhere.
Source: Inland Revenue, GST (goods and services tax) and Registering for GST. Rates checked October 2026.