For most people, just putting down your income and total spend will get you 99% of the way there
But, if you want to be more accurate, then input the following calculation the any other tax payments input field on the website
- Subtract any tax credits, or subsidies you have received
- Add your PIE (Portfolio Investment Entity) tax contribution
- Add your RWT (Resident Withholding Tax) contribution
- Based on your consumption of any specific item with levies, calculate any levies you have paid ie https://www.mbie.govt.nz/building-and-energy/energy-and-natural-resources/energy-generation-and-markets/liquid-fuel-market/duties-taxes-and-direct-levies-on-motor-fuels-in-new-zealand/