PAYE is the system that takes tax out of a New Zealand paycheck before the money reaches the bank account, and its name describes its mechanism: pay as you earn. Tax is withheld each pay period at the rate that pay period implies for the year, alongside KiwiSaver contributions, student loan repayments where they apply, and ACC levies handled through payroll. The result is a payslip with several deductions that look similar and mean different things. This guide separates them, works the tax brackets on two salaries, and explains what to check when pay changes mid-year.

What PAYE is, and what it is not

PAYE is withholding, not a separate tax. The employer calculates the tax due on each paycheck, deducts it, and passes it to Inland Revenue, so the employee never handles the year’s tax as a lump sum. At year end, Inland Revenue reconciles withholding against the year’s actual income, and most salary earners need no return at all, because withholding on a stable salary is accurate by construction. PAYE is therefore best understood as instalments of the year’s income tax, paid as the income arrives.

What PAYE is not is a flat rate. Each paycheck is annualised — treated as if it were earned every pay period for a year — and the annual tax on that figure is divided back into pay periods. A bonus paycheck is annualised the same way, which is why a bonus can look heavily taxed in its own period: the system treats it as if every period paid that much, and the reconciliation at year end corrects any over-withholding.

The brackets, worked on two salaries

New Zealand’s tax brackets apply marginally, so a salary of $70,000 does not pay the top applicable rate on all $70,000. The lower slices are taxed at the lower rates, and only the slice above each boundary attracts the higher rate. The calculator on this page applies the 2025/26 brackets and works the arithmetic in full, so a salary can be followed slice by slice from the first dollar to the last.

The comparison that clarifies the system is two salaries side by side. At a lower salary, most income sits in the lower brackets and the average rate is low. At a higher salary, the same lower slices are still taxed at the same lower rates — the higher salary does not re-tax the lower slices — and only the additional income faces the higher rates. That is why the average rate rises gently with income while the marginal rate jumps at boundaries, and why a raise can never reduce after-tax income through tax alone.

Monthly, weekly, and fortnightly: the same annual tax

Pay frequency changes the size and timing of withholding, not the annual tax. A monthly paycheck withholds roughly a twelfth of the annual tax, a fortnightly paycheck roughly a twenty-sixth, and a weekly paycheck roughly a fifty-second. The annual total is the same, give or take rounding in the final period, because the underlying calculation is annual in every case.

The practical consequence is that comparing paychecks across frequencies misleads. A fortnightly net figure looks smaller than a monthly net figure because it covers half the time, not because it is taxed more. Compare annual net, or compare a single pay period with the same frequency, and the comparison becomes honest.

KiwiSaver, student loans, and ACC: three different deductions

KiwiSaver is the easiest deduction to misunderstand, because it looks like a tax and is not one. It is a contribution to the employee’s own retirement savings, at a chosen rate, with a matching employer contribution on top. The money is not gone; it is saved, in the employee’s name, under KiwiSaver’s withdrawal rules. Opting out stops the contribution and the match together, which is a real cost disguised as a pay rise.

A student loan repayment is the opposite: money that reduces a debt, calculated as a percentage of income above a repayment threshold. ACC levies, handled through the payroll system for employees, fund the accident compensation scheme. The three sit together on the payslip, but one is savings, one is debt repayment, and one is insurance, and a take-home figure that treats them as one number hides three different stories.

When pay changes mid-year

A mid-year raise, a bonus, or a second job disturbs withholding for a few cycles, because each paycheck is annualised on its own. A bonus paycheck annualises high and withholds high; a first paycheck after a raise annualises the new salary for the whole year and withholds as if it had applied all year. Both effects are timing, and both are corrected at year-end reconciliation, which is why Inland Revenue’s end-of-year assessment, not any single payslip, is the final word.

The check is year-to-date: add gross pay and tax withheld so far and compare with the annual expectation for the salary. A steady drift away from expectation signals a wrong tax code, an unrecorded second job, or a KiwiSaver or student loan rate that changed without the payroll system being told. A single odd paycheck signals nothing except that annualisation did its job on an unusual period.

Checking your payslip in five minutes

First, confirm the gross figure matches the agreed salary for the period. Second, confirm the tax code is the one that matches your situation, including any second-job code. Third, check the KiwiSaver rate against the rate you chose, and confirm the employer contribution appears. Fourth, check the student loan deduction against the threshold and rate for your income. Fifth, compare the year-to-date tax with the calculator’s annual figure scaled to the periods elapsed. Five checks, one payslip, and any error will be sitting in one of them.

Frequently asked questions

How is PAYE calculated in New Zealand?

Each paycheck is annualised, tax is calculated on the annual figure using marginal brackets, and the result is divided back into pay periods. KiwiSaver, student loan repayments, and ACC levies are separate deductions on the same payslip.

Is PAYE a flat tax rate?

No. Tax is marginal: each slice of income is taxed at its own bracket rate, so only the slice above a boundary attracts the higher rate. Your average rate is always lower than your marginal rate once you pass the first bracket.

Why was my bonus taxed so heavily?

Because a bonus paycheck is annualised like any other: the system treats it as if every pay period paid that much, so withholding is high in that period. Year-end reconciliation corrects any over-withholding.

What is the difference between KiwiSaver and tax?

KiwiSaver is savings in your own name, with a matching employer contribution. Tax is money paid to the government. They appear together on the payslip but are fundamentally different.

Does pay frequency change my annual tax?

No. Monthly, fortnightly, and weekly cycles divide the same annual tax into different-sized periods. Compare annual figures, not single paychecks across frequencies.

What should I do if my year-to-date tax looks wrong?

Check the tax code, KiwiSaver rate, and student loan status one at a time against the calculator. A steady drift signals a wrong code or rate; a single odd paycheck is usually just timing.