GST Calculator NZ

Calculate GST (15%) and easily split an amount between business and personal use.

How to Calculate GST Manually

Here’s a comprehensive guide on how to calculate GST (Goods and Services Tax) in New Zealand, including methods for both removing GST (GST-inclusive) and adding GST (GST-exclusive) amounts, and how to handle amounts that are partly for business and partly for personal use.

Calculating GST:

1. Removing GST From a GST-Inclusive Amount:

A GST-inclusive amount is the total amount that includes GST. In New Zealand, the GST rate is 15%. However, when we remove GST from a GST-inclusive amount we need to use a special formula.

Formula: GST Amount = GST-Inclusive Price x 3 ÷ 23

Example: If your car insurance bill is $250 then 250 x 3 ÷ 23 = $32.61

So, the GST amount is $32.61, and the GST-exclusive amount is 250 – 32.61 = $217.39

2. Adding GST to a GST-Exclusive Amount:

A GST-exclusive amount is the amount before GST has been added.

Formula: GST Amount = GST-Exclusive Amount x 15%

Example: If you have a GST-exclusive amount of $100 and the GST rate is 15% then 100 x 0.15 = $15

So, the GST amount is $15, and the GST-inclusive amount is 100 + 15 = $115

Partial Business and Personal Use Calculation:

When an amount is partly for business use and partly for personal use, only the business use portion can be claimed for GST purposes.

Steps:

  1. Determine total GST on the amount: Use the formulas above to calculate the total GST on the full amount.
  2. Determine business use percentage: Identify the percentage of the expense that is for business use.
  3. Calculate business portion of GST: Multiply the total GST amount by the business use percentage.

Example: Let’s say you have a GST-inclusive amount of $230, and 60% of this amount is for business use.

  1. Calculate the total GST: 230 x 3 ÷ 23 = $30
  2. Calculate the business portion of GST: 30 x 0.60 = $18

So, the amount of GST you can claim for business purposes is $18.

In summary, by following these steps and formulas, you can accurately calculate and apportion GST for both GST-inclusive and GST-exclusive amounts, as well as for amounts that are partly for business and partly for personal use.

Related Resources