Secondary Income Tax Calculator

This calculator works out the correct secondary tax code for income you earn on top of your main job, whether that is a second job, freelance or contracting work, rental income, or any other regular earnings, and shows what it means for your take-home pay and year-end tax position. Enter your main job's gross annual salary, the amount and frequency of your secondary income, the type of income it is, and whether you have a student loan, and the calculator annualises your secondary earnings, adds them to your main income, and matches the total against IRD's secondary tax code thresholds. You get a recommended tax code (SB, S, SH, ST or SA, with the SL variant if you have a student loan), the flat PAYE rate that applies, and a breakdown of your main job deductions, secondary income deductions, and net secondary income received. It also estimates your year-end position, showing whether you are likely to owe a small tax bill or get a refund once IRD squares up your combined income, since the flat secondary rate rarely matches your marginal rate exactly. Use it before completing an IR330 for a new employer, or to check your current code still fits. Figures are indicative estimates based on current rates, not a substitute for advice from IRD or a tax professional.

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Updated April 2026  Current rates and legislation applied.

2026/27 Secondary Tax Code Reference

The correct secondary tax code depends on your estimated total income from all sources for the year. The threshold is your total gross income - main job plus all secondary income combined. You declare your secondary tax code on the IR330 form you give to each additional employer.

Why the Right Secondary Tax Code Matters

Secondary income is taxed at a flat rate - not the tiered rate applied to your main job. This is a deliberate simplification by the IRD. The flat rate is chosen to approximately match the marginal rate you would be paying if the income were added to your main job income. However, because it's a flat rate applied to all secondary income, it won't always match exactly. When your secondary income crosses a tax bracket boundary, you'll typically get a small refund at year end because the higher flat rate was applied to income that should have partially been taxed at the lower bracket rate.

Second Job vs Freelance vs Rental Income

The way you tell IRD about your secondary income depends on the source. For a second employer, you complete an IR330 tax code declaration and give it to your second employer. They deduct PAYE at the secondary rate each pay period. For freelance or contracting work, the rules around schedular payments and withholding tax apply instead - you may need to provide a Tax Rate Notification for Contractors (IR330C). For rental income and other non-PAYE sources, you typically declare this in your individual income tax return (IR3) at year end rather than having PAYE deducted at source.

Year-End Tax Returns

If you earn income from multiple sources you may be required to file an IR3 individual income tax return. This is separate from the automatic income tax assessment (ITA) that IRD produces for most employees. Having secondary non-PAYE income (such as rental income or significant freelance income) generally triggers an IR3 filing requirement. If you only have two PAYE income sources with correct tax codes, you may receive an automatic assessment from IRD after the year end.

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Reviewed and maintained. Last reviewed 2026-07-02 and checked on a twice-monthly cycle against IRD, RBNZ and Stats NZ. How we keep data current.

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