GST Calculator NZ | Inclusive or Exclusive | Prosaic Resources

Understanding GST's impact on product pricing can prove challenging. Whether you operate a business, freelance for clients, or shop as a consumer, computing GST represents a routine task throughout New Zealand.

How to calculate NZ GST

New Zealand's GST rate is 15%. Here's how to calculate it manually:

Adding GST to a price (exclusive → inclusive):

Multiply the GST-exclusive price by 1.15
Example: $100 × 1.15 = $115 (GST-inclusive price)
GST component: $115 − $100 = $15

Finding the GST in an inclusive price (inclusive → exclusive):

Divide the GST-inclusive price by 1.15
Example: $115 ÷ 1.15 = $100 (GST-exclusive price)
GST component: $115 − $100 = $15

Alternatively, to find just the GST component in an inclusive price: multiply by 3 and divide by 23.

Example: $115 × 3 ÷ 23 = $15

When do you need to calculate GST?

Invoicing clients — GST-registered businesses must add 15% GST to invoices for taxable supplies
Claiming GST back — knowing the GST component in a purchase helps you claim input tax credits
Quoting prices — being clear about whether a quote is GST-inclusive or exclusive prevents disputes
Filing GST returns — you need to report total GST collected and GST paid separately

GST registration threshold

You must register for GST if your taxable turnover exceeds (or is expected to exceed) $60,000 in any 12-month period. Once registered, you must charge GST on all taxable supplies and file regular GST returns with Inland Revenue.

Automate GST tracking with Prosaic

Prosaic's AI-powered GST cashbook automatically identifies GST on transactions and prepares your GST return data — starting at $5 per client per month. Learn more about how Prosaic can simplify your GST compliance.