How to Calculate GST in New Zealand
New Zealand's GST rate is 15%. Whether you need to add GST to a price, remove it from a GST-inclusive amount, or work out the GST component, here are the formulas and examples you need.
1. Adding GST to a Price
To calculate the GST-inclusive price, multiply the GST-exclusive amount by 1.15.
Formula: Price × 1.15 = Price incl. GST
Examples
$50.00 × 1.15 = $57.50 incl. GST
$100.00 × 1.15 = $115.00 incl. GST
$250.00 × 1.15 = $287.50 incl. GST
$1,000.00 × 1.15 = $1,150.00 incl. GST
2. Removing GST from a Price
To find the GST-exclusive price from a GST-inclusive amount, divide by 1.15.
Formula: Price incl. GST ÷ 1.15 = Price excl. GST
Examples
$57.50 ÷ 1.15 = $50.00 excl. GST
$115.00 ÷ 1.15 = $100.00 excl. GST
$287.50 ÷ 1.15 = $250.00 excl. GST
$1,150.00 ÷ 1.15 = $1,000.00 excl. GST
3. Finding the GST Component
To find just the GST amount from a GST-inclusive price, multiply by 3 and divide by 23. This works because GST is 15/115 (or 3/23) of the inclusive price.
Formula: Price incl. GST × 3 ÷ 23 = GST amount
Examples
$57.50 × 3 ÷ 23 = $7.50 GST
$115.00 × 3 ÷ 23 = $15.00 GST
$230.00 × 3 ÷ 23 = $30.00 GST
$1,150.00 × 3 ÷ 23 = $150.00 GST
Quick Reference Table
| Excl. GST | GST (15%) | Incl. GST |
|---|---|---|
| $50.00 | $7.50 | $57.50 |
| $100.00 | $15.00 | $115.00 |
| $200.00 | $30.00 | $230.00 |
| $500.00 | $75.00 | $575.00 |
| $1,000.00 | $150.00 | $1,150.00 |
| $5,000.00 | $750.00 | $5,750.00 |
| $10,000.00 | $1,500.00 | $11,500.00 |
GST on Invoices
If you are GST-registered, your tax invoices must clearly show the GST amount. A valid tax invoice needs to include:
- The words "tax invoice"
- Your name and GST number
- The date of the invoice
- A description of the goods or services
- The total amount charged including GST
- The GST amount charged (for invoices over $1,000)
Our free invoice generator automatically calculates and displays GST for you, so you don't have to do the maths yourself.
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