How to Work Out GST in NZ

Goods and Services Tax (GST) is part of almost every purchase in New Zealand. The current GST rate is 15%, which means it’s included in the total price you see at the checkout. But sometimes, you may need to know the price before GST or find out exactly how much GST is in the total.

How is GST Calculated in NZ?

There are two simple ways to calculate GST depending on the price you have:

1. If you have the price before GST

To find the total price (including GST):
Price before GST × 1.15 = Price including GST

Example:
$100 × 1.15 = $115

2. If you have the price including GST

To find the price before GST:
Price including GST ÷ 1.15 = Price before GST

Example:
$115 ÷ 1.15 = $100

To find just the GST amount:
Price including GST ÷ 1.15 × 0.15 = GST amount

Example:
$115 ÷ 1.15 × 0.15 = $15

This method is sometimes called “how to minus GST” since you are removing the GST portion from the total.

Quick Reference Formulas

• Add GST: Price before GST × 1.15
• Remove GST: Price including GST ÷ 1.15
• Find GST amount: Price including GST ÷ 1.15 × 0.15

Use a GST Calculator for Speed

While you can do the maths yourself, the fastest way is to use an online tool. Our GST Calculator NZ lets you enter any number and instantly see:

• Price before GST
• GST amount
• Price including GST

This saves time and avoids mistakes when you’re in a rush.