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.
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.
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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