InvioGST Calculator NZAdd or Remove 15% GST
Easily add or subtract 15% GST for your invoices and quotes, then use the same numbers when you build a tax invoice.
NZ GST Calculator (15%)
Instantly add or subtract GST for New Zealand invoices.
How to Calculate GST in New Zealand
The standard GST rate in New Zealand is 15%. Whether you are a sole trader, contractor, or small business, you need to calculate it correctly so the invoice totals and GST breakdown line up.
Formula to Add GST (Exclusive to Inclusive)
If you have a price before tax and need to add GST:
Formula to Remove GST (Inclusive to Exclusive)
If you have a total price and need to work backwards to find the amount before tax:
Why "Multiply by 3 divide by 23"?
Because 15% is 3/20 as a fraction. The math works out that 3/23 of the total price is the tax component. It is much more precise than using 0.1304...
Need to understand your broader GST obligations? See our Sole Trader Tax Guide for GST thresholds and registration requirements, or the NZ Tax Invoice Requirements guide for exactly what must appear on a valid GST invoice.
If you are still choosing a workflow, browse the full resources hub or read our comparison of free invoicing software in NZ to see when a quick calculator is enough and when saved client data starts to matter.