GST on $3,000
Both answers, because "GST on $3,000" means two different things depending on whether that figure already includes GST.
How much GST is on $3,000?
- If $3,000 is before GST: GST is $450.00 and the total becomes $3,450.00.
- If $3,000 already includes GST: the GST portion is $391.30 and the price before GST is $2,608.70.
- Working: $3,000.00 × 1.15 = $3,450.00 · $3,000.00 ÷ 23 × 3 = $391.30
$3,000, worked both ways
| Treating $3,000 as… | GST | Ex GST | Inc GST |
|---|---|---|---|
| a price before GST | $450.00 | $3,000.00 | $3,450.00 |
| a total that includes GST | $391.30 | $2,608.70 | $3,000.00 |
| an Australian price at 10% | $300.00 | $3,000.00 | $3,300.00 |
The two NZ rows are the ones people mix up. Charging $450.00 of GST on an invoice whose total is meant to be $3,000 would leave you $58.70 short once Inland Revenue takes its cut — the GST inside $3,000 is only $391.30.
The two calculations
Adding GST to a GST-exclusive price.
Finding the GST already inside a total.
Stripping GST out to get the ex-GST price.
Taking 15% of a GST-inclusive figure is the common error — it overstates the GST every time. Full guide, with the registration rules and the $60,000 threshold →
Do the next bit too
The number is the easy part. These take it the rest of the way.
Make the invoice
Turn this figure into a compliant GST tax invoice with your logo and download the PDF. The amount carries across automatically.
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