Example result based on the prefilled values.
Ex-GST Price
NZ$1,000.00
GST Amount
NZ$150.00
GST-Inclusive Price
NZ$1,150.00
GST Rate
15.00%
Continue your plan
Useful next calculations
When to use this calculator
- Before accepting a pay change, bonus, pension contribution, or salary-sacrifice option.
- When you want to compare employed, self-employed, or dividend-based income scenarios.
- When you need a simple take-home estimate before running payroll or filing returns.
- When you are approaching the £100,000 income level and want to understand the personal allowance taper effect.
- When you are planning a salary sacrifice arrangement and need to see the net pay impact before agreeing terms.
A realistic New Zealand planning example
Use these sample inputs as a quick scenario test, then change one variable at a time to compare outcomes.
Amount (NZ$)
1000
Calculation Type
Add GST to ex-GST price (exclusive → inclusive)
GST Rate
15% (standard NZ rate)
After entering these figures, review ex-gst price, gst amount and gst-inclusive price together rather than in isolation — each metric tells a different part of the story. Then rerun the tool with one input adjusted to see which variable has the biggest effect on all three outputs before you settle on a plan.
How to read your results
Ex-GST Price
Use this metric to compare scenarios side by side and understand how changes in the key inputs drive the final outcome. If the figure surprises you, isolate one variable at a time and rerun the calculation to identify which assumption is responsible.
GST Amount
Use this metric to compare scenarios side by side and understand how changes in the key inputs drive the final outcome. If the figure surprises you, isolate one variable at a time and rerun the calculation to identify which assumption is responsible.
GST-Inclusive Price
Use this metric to compare scenarios side by side and understand how changes in the key inputs drive the final outcome. If the figure surprises you, isolate one variable at a time and rerun the calculation to identify which assumption is responsible.
GST Rate
Use this metric to compare scenarios side by side and understand how changes in the key inputs drive the final outcome. If the figure surprises you, isolate one variable at a time and rerun the calculation to identify which assumption is responsible.
Method & assumptionsAuthoritative sources
New Zealand’s Goods and Services Tax (GST) has been charged at a flat rate of 15% since 1 July 2010, making it one of the simplest consumption taxes in the world. Unlike the UK’s VAT system, which has multiple rates, virtually all goods and services in New Zealand are taxed at the same rate — the main exceptions being zero-rated supplies such as exported goods and some financial services, and exempt supplies such as residential rent. Businesses registered for GST charge the tax on their sales, claim it back on their business purchases, and pay the net difference to Inland Revenue on a regular filing schedule. This calculator covers all three common calculations: adding GST to a price to produce a customer invoice total, removing GST from a quoted inclusive price to find the base cost, and identifying the GST component within an inclusive price for accounting purposes.
Getting the direction of your calculation right matters for accurate invoicing and GST return filing. Adding 15% to an ex-GST price (multiplying by 1.15) gives the GST-inclusive total. Removing GST from an inclusive price requires dividing by 1.15 — not subtracting 15% — because 15% of the inclusive price is not the same as 15% of the base price. For example, a $115 GST-inclusive price contains $15 of GST (13.04%), not $17.25. This calculator handles the correct formula in each direction so your figures are compliant with IRD requirements. For further guidance on GST registration, filing, and invoicing obligations, visit ird.govt.nz/gst.
Common mistakes
- !Using an assumption that is not supported by a current local quote, bill, statement or official source.
- !Treating a generic estimate as a lender, provider, payroll or tax authority decision.
- !Mixing monthly and annual inputs without converting them consistently.
- !Forgetting location-specific taxes, fees, eligibility rules or payroll deductions where they apply.
- !Testing only one scenario instead of checking how a cautious assumption changes the result.
What to do next
- Run a second scenario with a cautious assumption so you can see the downside clearly.
- Compare the result with the related calculators below before making a decision.
- Check current local rules, eligibility and provider terms before applying or committing money.
- Keep a record of the assumptions so you can update the estimate when a quote, bill or pay figure changes.
- Use the result to prepare better questions for a lender, provider, adviser or employer rather than treating it as a final answer.
Frequently asked
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