GST on $10
Both answers, because "GST on $10" means two different things depending on whether that figure already includes GST.
How much GST is on $10?
- If $10 is before GST: GST is $1.50 and the total becomes $11.50.
- If $10 already includes GST: the GST portion is $1.30 and the price before GST is $8.70.
- Working: $10.00 × 1.15 = $11.50 · $10.00 ÷ 23 × 3 = $1.30
$10, worked both ways
| Treating $10 as… | GST | Ex GST | Inc GST |
|---|---|---|---|
| a price before GST | $1.50 | $10.00 | $11.50 |
| a total that includes GST | $1.30 | $8.70 | $10.00 |
| an Australian price at 10% | $1.00 | $10.00 | $11.00 |
The two NZ rows are the ones people mix up. Charging $1.50 of GST on an invoice whose total is meant to be $10 would leave you $0.20 short once Inland Revenue takes its cut — the GST inside $10 is only $1.30.
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.
invoice.amit.marketing →Never file a GST return again
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
Ten free tools that talk to each other — send hours or an accepted quote straight into an invoice without retyping a thing. No signup on any of them.