No. This site reports what the published rules are and what the arithmetic gives. It does not know your circumstances, and it never tells you what to do. For anything binding, talk to a chartered accountant or contact Inland Revenue.

Methodology

Q: Why does the calculator differ from my payslip by a few cents?

Inland Revenue truncates at defined points inside each pay period rather than calculating annually and dividing. An annual figure divided by 26 will therefore differ by cents from 26 real fortnightly payslips. The calculator provides both paths.

Q: How often are the rates updated?

Every 1 April, when the tax year changes. The current figures were last verified on 30 July 2026 against Inland Revenue's published sources. Every rate lives in a single file, so the annual update cannot leave one page stale.

What this calculator models, what it deliberately leaves out, and where every figure comes from. Published so you can check the arithmetic rather than trust it.

This calculator implements Inland Revenue's Payroll Calculations and Business Rules Specification for the 2026–27 tax year, and its output is checked against every row of IRD's own Payday Software Developers Casebook. Rates were last verified on 30 July 2026.

What the calculator models

Deductions and credits the engine calculates
Component	Basis
Income tax	Progressive brackets, applied to annual taxable income
ACC earners' levy	1.75% of liable earnings, capped at $156,641
KiwiSaver employee deduction	3.5%, 4%, 6%, 8%, 10% of gross pay
KiwiSaver employer contribution	3.5% of gross, with the age test applied
ESCT	Banded on the ESCT rate threshold amount
Student loan	12% of earnings above $24,128
Independent earner tax credit	Including the abatement curve
Extra pay	Bonuses, holiday pay lump sums, redundancy
Payroll giving	Capped at the income tax element of PAYE

What it deliberately does not model

Publishing this list is the point. A calculator that implies it covers everything is more dangerous than one that states its edges.

Working for Families. It is a payment from Inland Revenue rather than a deduction from your pay, and it depends on household composition this calculator never asks about.
Child support and Commissioner deductions. These are directed per person by Inland Revenue and cannot be derived from a salary. A student loan deduction directed by the Commissioner can add up to 5% on top of the standard rate.
Non-standard pay cycles. Four weekly is supported in the period functions, but irregular and casual patterns with no fixed period are not.
The prescribed investor rate on KiwiSaver earnings. That taxes what your fund earns, not what your employer pays you, so it never appears on a payslip.
Fringe benefits and share schemes. Employee share scheme benefits are treated as extra pay when an employer chooses to deduct tax, which is optional and unknowable from a salary.
Part-year employment. The annual view assumes a full year at the income you enter. Starting a job in November produces a different end-of-year result.

The one divergence we chose on purpose

On a high secondary income the annual and per-period paths disagree, and neither is wrong. The annual path caps the ACC earners' levy at $2,741.22, because across a full year that is the statutory maximum. The per-period path does not cap, because a payroll system processing one payday cannot know what the rest of the year holds.

Your payslip matches the per-period path. Your end-of-year square-up matches the annual one. The gap between them is the refund. We implement both rather than picking whichever looks tidier, and there is a test asserting the divergence still exists.

Rounding

Truncation, not rounding. Inland Revenue truncates toward zero at defined points. Using rounding instead shifts results by cents per period, and cents are exactly what people check against a payslip.
ESCT applies to whole dollars. The employer contribution is truncated to whole dollars before the ESCT rate is applied.
Displayed percentages are computed, not typed. Every rate on this site renders from a stored decimal through one formatter. This avoids the floating point artefact that turns 1.75% into 1.7500000000000002 on pages that build the string by multiplication.

Where the figures come from

Every statutory rate, threshold and cap on this site is stored once, in a single file, with a citation to the Inland Revenue page it came from. No page contains a typed-in figure.

This is a structural guarantee rather than an editorial promise. Two pages cannot disagree about the ACC cap, because neither page contains it. When a rate changes on 1 April, it changes in one place and every page that mentions it updates at once.

The primary sources are Inland Revenue's published rate pages, the Payroll Calculations and Business Rules Specification, and the Employer's Guide. Holiday pay figures come from Employment New Zealand, because the Holidays Act is administered separately from the tax system. Each page lists the exact sources it drew on.

Testing

The calculation engine has no interface dependencies, which means it can be tested directly. Several assertions are pinned to hand-computed values rather than to whatever the code currently returns.

If a bracket moves and someone updates the rate without recomputing, those assertions fail loudly. That failure is the point of writing them that way. The suite also asserts that components always reconcile back to gross, that zero income produces zeroes rather than NaN, and that malformed input is coerced rather than propagated.

What this site is not

It is not tax advice, not a payroll system, and not a substitute for your employer's records. It reports published rules and the arithmetic they produce. If a figure here disagrees with your payslip, the payslip is the document with legal standing, and the difference is worth asking your employer about.

rates changelogWhat changed, and when
how PAYE is calculatedThe formula, step by step
the New Zealand tax yearWhy 1 April matters here
PAYE calculatorThe tool this describes

Common questions

How accurate is this PAYE calculator?

The engine reproduces every row of Inland Revenue's Payday Software Developers Casebook 2026-27 exactly. That casebook is the reference set payroll vendors certify their own systems against, so matching it is the strongest accuracy claim available short of being a payroll system. Those comparisons run as automated tests on every change.

Why does the calculator differ from my payslip by a few cents?

Inland Revenue truncates rather than rounds, at defined points inside each pay period, rather than calculating an annual figure and dividing. An annual figure divided by 26 will therefore differ by cents from 26 actual fortnightly payslips. That divergence is real, not an error, and the engine implements both paths deliberately.

Is this tax advice?

No. This site reports what the published rules are and what the arithmetic gives on the numbers you enter. It does not know your circumstances and never recommends a course of action. For anything binding, talk to a chartered accountant or contact Inland Revenue directly.

How often are the rates updated?

Every 1 April, when the tax year turns over. The current figures were last verified on 30 July 2026. Every rate lives in one file, so an update cannot leave one page disagreeing with another. The dated record is on the rates changelog.

Where these figures come from

2026–27 tax year (1 April 2026 – 31 March 2027). Last verified 30 July 2026.

rates changelogEvery figure, and the date it changed
how PAYE is calculatedThe formula this implements
New Zealand PAYE ratesIncome tax and ACC as one rate
New Zealand tax codesWhat the engine needs to be correct