Service Fee True Cost Calculator NZ 2026
Rates current for the 2026/27 tax year. Reviewed 5 August 2026.
Nobody pays the advertised price for a business service. Two reliefs sit between the headline and your bank balance, and neither appears on a pricing page. The first is GST. If you are registered, the GST charged on the fee is reclaimed through your GST return, so it costs you nothing at all; if you are not registered, and most operators below the $60,000 turnover threshold are not, it is a genuine 15 percent added to everything. The second is the income tax deduction. A fee incurred in earning your business income reduces your taxable profit, so the tax you pay falls by the fee multiplied by your marginal rate. At 33 percent, a third of what you spend comes back. Put together, a fee advertised at $1,500 plus GST is $1,725 to pay, $1,500 after the GST claim, and $1,005 after the deduction. That last figure is what the service actually costs, and it is the only one worth comparing between providers. This calculator converts any headline into it, handles GST-inclusive and GST-exclusive quotes correctly, and shows how the answer moves with your income.
From headline to real cost
The same fee at different incomes
The deduction is relieved at your marginal rate, so the identical fee costs less the more you earn.
| Annual profit | Marginal rate | Deduction saves | Real cost |
|---|
Comparing two quotes correctly
The mistake is comparing one provider's GST-inclusive price against another's GST-exclusive one, and it is easy to make because both are advertised as a single number with the basis in small print. For a registered business the GST washes out on both sides, so the comparison should be made on the GST-exclusive figures. For an unregistered business it does not wash out, so the comparison should be made on the GST-inclusive figures. Using the wrong pair can reverse which quote looks cheaper when the two are close, and the difference is 15 percent, which is larger than most price gaps between competitors.
Why the deduction narrows gaps rather than changing winners
Because both fees under comparison are usually deductible, the deduction shrinks each of them by the same proportion. The cheaper option stays cheaper. What changes is the size of the difference in money you actually feel: at a 33 percent marginal rate, a $500 gap in headline price is a $335 gap in real cost. That can be enough to make a more expensive service worth choosing on scope, and it is the reason comparing headline prices tends to overstate how much the decision matters.
Worked example
A GST-registered sole trader with $120,000 of profit is quoted $1,500 plus GST. They pay the provider $1,725.00, then reclaim $225.00 of GST through their return, leaving $1,500.00. That amount is deductible, and at a marginal rate of 33 percent it reduces their tax bill by $495.00. The real cost is $1,005.00, or $83.75 a month.
The same quote to someone not registered for GST, with profit of $40,000, looks very different. They cannot reclaim the GST, so the cost after GST is the full $1,725.00, and their deduction is relieved at 17.5 percent rather than 33 percent. Their real cost is $1,423.13, which is 42 percent more than the registered trader pays for exactly the same service.
How this is calculated
If the advertised fee excludes GST, the amount paid is the fee plus 15 percent; if it includes GST, the amount paid is the fee itself. A GST-registered payer reclaims the GST portion, taken as three twenty-thirds of the GST-inclusive amount. The remaining cost is deductible, and the tax saved is calculated by comparing the tax on your profit with the tax on your profit less that cost, rather than applying a single rate, so a fee that spans a bracket boundary is relieved correctly. Rates are those in force from 1 April 2025: 10.5% to $15,600, 17.5% to $53,500, 30% to $78,100, 33% to $180,000, and 39% above that.
Related NZ calculators
- Percentage Fee vs Fixed Fee Calculator for comparing two pricing models
- Deduction Value Calculator for what any deduction is worth
- GST Calculator for adding and removing GST
- GST Registration Threshold Calculator for whether to register
- Self-Employed Take-Home Calculator for what you keep overall