Imagine you're 15 and someone hands you $115
You sell a lawnmowing job for $100. Easy. The lawn looks great, you get paid, you go home with a hundy. Now your accountant says you have to add 15% GST to your invoice — so the customer pays $115 instead.
You feel like you just got a pay rise. You didn't.
That extra $15 isn't yours. It's GST. It belongs to the New Zealand government (IRD), and you're temporarily holding it on their behalf. When GST return time comes, you send that $15 to IRD. Your real income from the job is still $100.
Three roles, three outcomes
Whenever GST shows up in NZ, three different parties are involved. Here's what actually happens to each one, in plain English:
Buys the service for $100 + $15 GST. Hands over $115. Can't claim it back. They are the one who's truly $15 worse off.
Charges 15% on sales, claims 15% back on expenses, sends the difference to IRD. Their real income is the GST-exclusive amount.
Doesn't charge it directly — businesses do that. But every dollar of GST collected on every transaction in NZ ends up here.
A real-world example: the tradie
Mike's a sparkie. He quotes a kitchen rewire at $2,000 + GST. The customer pays him $2,300. Mike spent $400 + GST on materials.
| Income (GST collected from customer) | $300 |
| GST paid on materials (claimed back) | −$60 |
| Net GST owed to IRD | $240 |
| Mike's actual income from the job | $2,000 |
The trap is pricing the job "GST inclusive" by accident. If Mike quotes "$2,000 all up" instead of "$2,000 + GST", his real income drops to $1,739 — because $261 of that $2,000 is GST that has to go to IRD. Same job, $261 less in his pocket.
A real-world example: the insurance agent
Sarah earns commissions from a life insurance company. She's GST-registered.
Her commission on a policy is $1,000. The insurer pays her $1,000 + GST = $1,150. Sarah's actual income is still $1,000 — the $150 is GST that flows through her bank account to IRD.
The trap for commission earners: many feel like they "lose 15%" because $150 leaves their account on GST return day. But that money was never theirs. It's like a courier dropping off a package at your house and you keeping it because it landed on your doorstep.
If GST is added on top → the customer pays it.
If GST is included in the price → you pay it.
The 3 simple rules to never lose money to GST
Write "$X + GST" on every quote. Never just "$X total". This single habit prevents 90% of the income loss.
When a customer pays you, move 15% of the invoice to a dedicated GST holding account. It stops you spending IRD's money by mistake.
Know what you owe IRD before the return is due. The shock isn't the GST — it's finding out the day before you have to pay it.
So when does GST actually cost you something?
Three real-world situations where GST does eat into your income — and they're all about pricing, not about GST itself:
- You quoted "GST inclusive" without realising — you absorbed the 15%.
- Your competitors don't charge GST (they're under the threshold) and you can't raise prices without losing them.
- You spent the GST money before the GST return was due. Cashflow squeeze, not a tax problem.
"GST isn't your cost — it's your customer's cost. You're collecting it for IRD. It only becomes your problem when your pricing absorbs it instead of passing it on."
What this looks like for you
Most NZ small business owners and contractors don't lose sleep over tax. They lose sleep over cashflow surprises — and GST is the most common cause.
Here's what we do for clients on our monthly subscription:
- Set up your books so GST is automatically separated from your real income the moment a job is invoiced.
- Email you a monthly tax position showing the exact GST you owe — before the GST return is due, so it's never a shock.
- Make sure every quote you send is priced GST-exclusive by default in your invoicing tool.