Tax Year
New Zealand's tax year (also called the income year) runs from 1 April to 31 March — not the calendar year. When we refer to the '2025-26 tax year', we mean 1 April 2025 to 31 March 2026. This affects which tax rates, thresholds, and ACC levy caps apply to your income.
Most individuals have their tax automatically assessed by IRD after 31 March each year, using information reported by employers, banks, and other payers. If your tax affairs are straightforward (salary/wages only), you'll receive an income tax assessment in your myIR account — you don't need to file a return.
If you have more complex income (self-employment, rental, overseas) you'll need to file an IR3 tax return, typically due by 7 July (or 31 March the following year if you use a tax agent). Keep records of all income and expenses for at least 7 years.
How it works
The 1 April to 31 March tax year is what determines which set of rates, thresholds, and caps apply to your income — this is why you'll see figures labelled things like '2025-26' rather than a plain calendar year, since the tax year straddles two calendar years. Any calculator or tax figure you use needs to reference the correct tax year to give you an accurate answer.
For most salary and wage earners, nothing needs to happen at your end when the tax year ends — IRD automatically works out your income tax position using the information reported by your employer, bank, and other payers throughout the year, then issues an income tax assessment through myIR showing any refund due or tax to pay.
If your income isn't fully covered by PAYE — self-employment, rental income, or overseas income, for example — you'll need to file an IR3 return yourself, generally due by 7 July (or 31 March the following year if you file through a registered tax agent). It's good practice to keep income and expense records for at least seven years in case IRD needs to review your position.
Frequently asked questions
Why doesn't New Zealand's tax year match the calendar year?
New Zealand's tax year runs 1 April to 31 March rather than January to December, so tax figures and rates are always described by the specific tax year they apply to, such as 2025-26.
What happens automatically after 31 March each year?
IRD uses the income information reported by employers, banks, and other payers during the year to automatically work out your income tax position and issue an assessment through myIR.
How long should I keep my tax records for?
It's recommended to keep records of your income and expenses for at least seven years, in case IRD needs to review or query your tax position for a past year.
Related Terms
IRD
Inland Revenue Department (IRD), commonly known as Inland Revenue or simply IRD, is the New Zealand government agency responsible for collecting taxes, distributing social support payments, and enforcing tax compliance.
Income Tax
New Zealand income tax is calculated using a progressive bracket system.
Tax Return / IR3
An IR3 is New Zealand's individual income tax return — an annual declaration of all your income, expenses, and tax credits filed with IRD.