If you are wondering how to calculate NZ GST you have come to the right place. In this guide we are going to explain how you can calculate the GST exclusive price, inclusive price, and GST component.
Calculating From GST Exclusive Price
If you have the GST exclusive price and want to find the GST inclusive price and the GST component, you can do the following:
The Right Way
GST Inclusive Price
GST Inclusive Price = GST Exclusive Price x 115%
GST Inclusive Price = $100 x 1.15
GST Inclusive Price = $115
GST Component
GST Component = GST Exclusive Price x 15%
GST Component = $100 x 0.15
GST Component = $15
GST Inclusive Price if you already have both the Exclusive Price and Component
GST Inclusive Price = GST Exclusive Price + GST Component
GST Inclusive Price = $100 + $15
GST Inclusive Price = $115
GST Component if you already have both the Inclusive and Exclusive Price
GST Component = GST Inclusive Price - GST Exclusive Price
GST Component = $115 - $100
GST Component = $15
Calculating From GST Inclusive Price
If you are working from the GST inclusive price and want to find the exclusive price and the GST component, it is easy to get tripped up. It’s not as simple as just doing the opposite of what we did above:
The Right Way
GST Component
GST Component = GST Inclusive Price x 3 ÷ 23
GST Component = $115 x 3 ÷ 23
GST Component = $15
GST Exclusive Price
GST Exclusive Price = GST Inclusive Price - GST Component
GST Exclusive Price = $115 - $15
GST Exclusive Price = $100
The Wrong Way
GST Component
GST Component = GST Inclusive Price - 15%
GST Component = 115 x 0.15
GST Component = $17.25
GST Exclusive Price
GST Exclusive Price = GST Inclusive Price - GST Component
GST Exclusive Price = $115 - $17.25
GST Exclusive Price = $97.75
As you can see this is not the correct GST exclusive value if we compare it to the calculations in the “Calculating From GST Exclusive Price” section (we started with $100). This is because if we simply subtract 15%, we wind up with a GST component of $17.25, not the correct $15 amount.
Calculating From GST Component/Amount
If you only have the GST component/amount, you can work out the GST inclusive and exclusive price by essentially reversing the formulas we gave you above:
GST Inclusive Price
GST Inclusive Price = GST Component x 23 ÷ 3
GST Inclusive Price = $15 x 23 ÷ 3
GST Inclusive Price = $115
GST Exclusive Price
GST Exclusive Price = GST Inclusive Price - GST Component
GST Exclusive Price = $115 - $15
GST Exclusive Price = $100
Use Our Calculator
If you don’t want to do this all yourself, check out our handy calculator here. Alternatively, if you want to learn how to apply these formulas in Excel, check out How to calculate GST in Excel.