NZ Tax Code Picker (IR330 Helper)

Picking the wrong box on your IR330 form is one of the easiest ways to end up under-paid each payday or land a surprise tax bill at year end. This tool asks the same questions as the IR330 and works out the exact tax code your employer needs, using the 2026/27 thresholds. Tell it whether this is your main job or a secondary one, then enter your expected annual income (and, for a secondary job, your combined income across all jobs, since that total sets your secondary rate). Add whether you have an active student loan and, for a main job, whether you already receive Working for Families, a main benefit or NZ Super, since these rule out the Independent Earner Tax Credit. You then get your code, from M or ME through to SB, S, SH, ST or SA, with an SL suffix where it applies, a plain-language explanation of why it fits your circumstances, and an annual deductions estimate showing tax, ACC levies, student loan repayments and take-home pay. A mismatch, such as total income below the secondary job's own income, triggers a warning so you can check your figures. Use the result on your IR330 straight away, since leaving the form blank forces your employer onto the 45% no-notification rate. For complex cases, confirm with IRD or a tax adviser.

Updated April 2026  Implements IR330 selection logic per IRD 2026/27 thresholds.
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Step 1: Income source

If you have multiple jobs, the highest-paying one uses a primary code (M / ME). All others use secondary codes (S / SH / ST / SA / SB).

Step 2: Income

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Step 3: Student loan

Add SL suffix if yes. Repayment is 12% of every dollar over $24,128 (annual) on your primary job, or 12% of all gross on secondary jobs.

Step 4: Other income / benefits (primary code only)

If you receive any of these, you cannot use the ME code (which includes the IETC). The IETC and these benefits cannot be received at the same time.

Primary tax codes explained

  • M - Main job, no IETC. Use if your annual income is below $24,000 or above $70,000, or if you receive Working for Families, a main benefit, or NZ Super.
  • ME - Main job + Independent Earner Tax Credit ($520/year). Use if your annual income is between $24,001 and $70,000 AND you don't receive WfF, main benefit, or NZ Super.
  • M SL - Main job with student loan deductions (12% over $24,128 annual threshold).
  • ME SL - Main job + IETC + student loan.

Secondary tax codes explained

  • SB - 10.5% - Use if your TOTAL income from all sources is under $15,600.
  • S - 17.5% - Use if total income is $15,601 to $53,500.
  • SH - 30% - Use if total income is $53,501 to $78,100.
  • ST - 33% - Use if total income is $78,101 to $180,000.
  • SA - 39% - Use if total income is over $180,000.
  • Add SL to any of the above for a student loan secondary deduction (e.g. S SL, SH SL).

Other tax codes

  • CAE - Casual agricultural employees (17.5% flat).
  • EDW - Election day workers (17.5% flat).
  • NSW - Non-resident seasonal workers (10.5% flat for RSE workers).
  • WT - Withholding tax for schedular payments (contractor income).
  • STC - Special tax code (only with IRD certificate).

The 45% no-notification trap

If you don't give your employer a completed IR330 form (with your IRD number and tax code), they must deduct PAYE at the no-notification rate of 45% on every dollar. This is higher than even the 39% top marginal rate. Always submit an IR330 on day one of any new job.

Sources

This tool provides general guidance only. If your situation is complex (multiple jobs, partial-year income, schedular payments, special STC), confirm with IRD or a tax adviser before submitting your IR330.

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