Changing Your Tax Code

Q: How do I change my tax code in New Zealand?

Complete a new IR330 tax code declaration with the correct code and give it to your employer. Payroll applies it from the next pay run. You do not need Inland Revenue's approval and there is no limit on how many times you can do it. If you have more than one job, each employer needs its own form.

Q: How do I find out what tax code I am on?

Your payslip shows it, usually next to your PAYE line. It also appears in myIR under your income details for each employer, and any payroll self-service portal your employer uses will show it. If none of those are available, payroll can tell you what is currently on file.

Q: When does a new tax code take effect?

From the next pay run after your employer processes the form. It is never backdated, so the pay you have already received keeps the tax that was withheld at the time. The difference for the earlier part of the year is settled in the end-of-year assessment after 31 March.

Q: Will I be refunded if I was on the wrong tax code?

If too much came out, yes. Inland Revenue works out the tax genuinely due on your income for the whole year and compares it with everything withheld, then refunds the difference. If too little came out, the same calculation produces a bill instead. Changing the code early keeps either figure small.

Q: Have the New Zealand tax codes themselves changed?

The set of codes has been stable, but the rates behind them and the independent earner tax credit both changed on 31 July 2024. The credit now runs to $70,000 rather than $48,000, and the secondary code rates became 12.25%, 19.25%, 31.75%, 34.75% and 40.75%. The next scheduled change is the KiwiSaver rate rise on 1 April 2028.

A tax code is a forecast of your year, so it goes out of date when the year does something else. Here is where to find the one you are on, how to replace it, and what happens to the paydays that used the old one.

To change your tax code, give your employer a new IR330 with the correct code on it. Payroll applies it from the next pay run. It is never backdated, and nothing needs approving. One form per employer, as many times a year as your circumstances change.

Finding the code you are on now

Four places show it, and they should all agree. If two of them disagree, the one payroll is using is the one taking money out of your pay.

Your payslip. Usually printed beside the PAYE line, as two or three characters such as M, ME or SH, with SL after it if a student loan is being deducted.
myIR. Under your income details, each employer is listed with the code they are filing against.
Your payroll portal. Most systems show the current code on the same screen as your bank account and KiwiSaver rate.
Payroll themselves. They hold your signed IR330 and must keep it for seven years.

Comparing that code against the one you should be on takes about a minute with the tax code finder.

How to change it

Work out the correct code.It depends on whether this is your highest-earning job, your total income from every source, whether a student loan is still being repaid, and whether you receive Working for Families, an income-tested main benefit, NZ Superannuation or a Veteran's Pension.
Complete a new IR330. The same form you filled in when you started. Nothing marks it as a change, because a later declaration simply replaces the earlier one.
Give it to your employer. Not to Inland Revenue. Payroll is the only party that can act on it.
Check the next payslip. The new code should appear on the first pay run processed after they receive the form. If it has not, the form has not reached payroll.
Repeat for every other employer. Changing your main job's code often changes the right answer for your second job too, because both are chosen from the same total income.

A new code fixes the future and nothing else

The change applies from the next pay run. Nothing is recalculated, no adjustment appears on your payslip, and the pay you have already received keeps whatever was withheld at the time. That is not payroll being unhelpful. PAYE is calculated pay period by pay period, and a period that has closed cannot be reopened.

The earlier part of the year is settled once, in the end-of-year assessment after 31 March. Inland Revenue works out the tax genuinely due on your whole year, subtracts everything withheld under both codes, and issues a refund or a bill for the difference. Changing early does not change that total. It changes how much of it is left to settle.

What a change is actually worth

Four common corrections, and the figure attached to each. Two of them put money in your account sooner and two of them stop a bill growing.

Common tax code changes and what each one is worth
Change	Why it happens	What it is worth
M to ME	Total income of $24,000 to $66,000 with none of the exclusions	$10.00 a week more in your account
SB to SH on a second job	The code was picked from the second job's own pay rather than your $71,000 total	$1,755 a year that was never withheld
S to M on your only job	The other job ended and the secondary code stayed behind	$1,092 a year over-withheld on $45,000
Adding the SL suffix	A student loan that payroll was never told about	12% above $24,128 a year, assessed either way

Only one of those four changes your tax for the year. Moving from M to ME claims the $520 independent earner tax credit through your payslip instead of waiting for it, and on M an eligible earner still receives it at year end. The other three move money between your paydays and your assessment without changing the total.

When your code stops being right

None of these need a reason given to anybody. They are simply the events that make a previously correct declaration wrong.

You start a second job. The new job needs a secondary code chosen on your total income, and your existing job keeps its main-income code.
A job ends. If the job that continues is carrying a secondary code, it is now your main income and needs M or ME. Leaving it on S over-withholds $1,092 a year on $45,000 of income.
Your total income crosses a band boundary. The secondary code bands change at $15,600, $53,500, $78,100 and $180,000. A pay rise on one job changes the correct code on the other.
Your independent earner tax credit entitlement starts or ends. The band is $24,000 to $70,000 of total income, and any of Working for Families, an income-tested main benefit, NZ Superannuation or a Veteran's Pension ends it regardless of income.
Your student loan is repaid. Inland Revenue notifies your employer, and the SL suffix comes off from the next pay run. Removing it yourself first risks under-repaying.

Changes to the tax codes themselves

The other reading of this question is whether the codes have changed rather than whether yours has. The set of codes has been stable for years. What moves is the rates behind them, and the last substantial change was on 31 July 2024.

That date reset the tax brackets and widened the independent earner tax credit, which had run out at $48,000 and now runs to $70,000. The secondary code rates that followed are the ones in force for 2026–27: 12.25%, 19.25%, 31.75%, 34.75% and 40.75%, each including the ACC earners' levy.

The next scheduled change does not touch tax codes at all. The KiwiSaver employee minimum and the compulsory employer contribution both rise to 4% on 1 April 2028, which changes your take-home pay without changing the code on your payslip. KiwiSaver contribution rates.

Common questions

How do I change my tax code in New Zealand?

Complete a new IR330 with the correct code and give it to your employer. Payroll applies it from the next pay run. No approval is needed and there is no limit on how often you can do it. With more than one job, each employer needs its own form.

How do I find out what tax code I am on?

Your payslip shows it, usually beside the PAYE line. It is also in myIR under your income details for each employer, and in any payroll portal your employer runs. Failing that, payroll can tell you what is on file.

When does a new tax code take effect?

From the next pay run after payroll processes the form. It is never backdated, so pay you have already received keeps the tax withheld at the time. The earlier part of the year is settled in the assessment after 31 March.

Will I be refunded if I was on the wrong tax code?

If too much came out, yes. Inland Revenue compares the tax genuinely due on your year against everything withheld and refunds the difference. If too little came out, the same calculation produces a bill. Changing the code early keeps either figure small.

Can Inland Revenue change my tax code without me asking?

Yes, in specific cases. Inland Revenue notifies your employer directly when your student loan is repaid so the SL suffix comes off, and when a tailored tax code is issued. Payroll must act on that notice. Everything else starts with a new IR330 from you.

Have the New Zealand tax codes themselves changed?

The set of codes has been stable. The rates behind them and the independent earner tax credit both changed on 31 July 2024, and the credit now runs to $70,000 rather than $48,000. The next scheduled change is the KiwiSaver rate rise on 1 April 2028.

Where these figures come from

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

what tax code am IFive questions, one answer
the IR330 tax code declarationThe form a change is made on
New Zealand tax codesEvery code and rate in one table
secondary taxWhere wrong codes cost the most
the New Zealand tax year1 April to 31 March, and what the square-up settles
how to read a New Zealand payslipWhere your current code is printed