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KiwiTools guide

Data sources and assumptions

We distinguish official rules and external datasets from illustrative presets and the values you provide.

Tax-year rules (2027)

Income-tax brackets, the 1.75% ACC earners' levy and its $156,641 cap, KiwiSaver settings, student-loan settings and applicable tax-credit settings are centralised from Inland Revenue material for 1 April 2026 to 31 March 2027. They must be reviewed before a new tax year is published.

Energy, transport and employment guidance

Electricity Authority, EECA and MBIE material supports power-bill, appliance and solar context. NZTA supports RUC and vehicle guidance. Employment New Zealand supports public-holiday, annual-leave and pay concepts. Rules that affect a result are kept separate from editable prices and usage assumptions.

Mortgage, property and comparison inputs

Rates, property values, deposits, terms, council assessments, buying costs, rent, vacancy, fuel prices, flight costs, mobile-plan prices and ownership assumptions are entered or editable planning values. Defaults are examples, not offers, national averages or predictions. Relevant context is drawn from Reserve Bank, Settled, Sorted, Commerce Commission and Consumer Protection guidance.

Addresses, school zones and maintained dates

School-zone results depend on address matching and Ministry of Education mapped enrolment-zone data. Boundaries and enrolment schemes can change, and near-boundary results require confirmation. Public-holiday and regional-anniversary dates are maintained as application data and should be checked against official guidance for important leave planning.

Appliance and scenario presets

Wattages, duty cycles, kWh-per-cycle values, growth assumptions and example costs are editable starting points. They are not measurements of every model or predictions of future prices. Labels, manuals, bills, quotes, measured use and provider terms should take priority.

Review and corrections

Each tool page identifies its relevant sources, assumptions and review context. Material rule, dataset or formula changes should be updated with the related calculation logic and supporting content. Corrections can be reported through the contact form linked in the footer.

Estimate only: Calculator results are estimates based on the values entered and the assumptions shown. Check important decisions against the relevant provider or official source.