GST on $400
Both answers, because "GST on $400" means two different things depending on whether that figure already includes GST.
How much GST is on $400?
- If $400 is before GST: GST is $60.00 and the total becomes $460.00.
- If $400 already includes GST: the GST portion is $52.17 and the price before GST is $347.83.
- Working: $400.00 × 1.15 = $460.00 · $400.00 ÷ 23 × 3 = $52.17
$400, worked both ways
| Treating $400 as… | GST | Ex GST | Inc GST |
|---|---|---|---|
| a price before GST | $60.00 | $400.00 | $460.00 |
| a total that includes GST | $52.17 | $347.83 | $400.00 |
| an Australian price at 10% | $40.00 | $400.00 | $440.00 |
The two NZ rows are the ones people mix up. Charging $60.00 of GST on an invoice whose total is meant to be $400 would leave you $7.83 short once Inland Revenue takes its cut — the GST inside $400 is only $52.17.
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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Hnry takes your income, works out the GST, ACC and income tax, pays them and files the returns. Built for NZ sole traders.
See Hnry →GST on other amounts
The rest of the toolkit
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