Secondary job tax applies when you work for more than one job and earn income from more than one source at the same time in New Zealand. Your primary or main job uses the standard M (or ME) tax code which has a different tax slab compared to the secondary job tax codes. All additional job must use a secondary tax code (SB, S, SH, ST, or SA). The secondary tax code ensures your additional income is taxed at a flat rate that matches the tax bracket your total combined income falls into. This setup is to prevents you from being under-taxed during the tax year and receiving a large tax repayment bill at the end of the financial year.

To choose the correct secondary tax code, you must understand how much you earn from other sources combined. For the 2026-2027 tax year, the codes are: SB (10.5%) if total income is up to $15,600, S (17.5%) for $15,601–$53,500, SH (30%) for $53,501–$78,100, ST (33%) for $78,101–$180,000, and SA (39%) for income over $180,000. There is a flowchart on the IR330 form with which you can determine what secondary code applies to you.

No, secondary tax is not an additional or extra tax. This is a major misconception among employees in NZ. It is simply a different method of collecting the same income tax you would owe anyway. At the end of the tax year (31 March), Inland Revenue performs an automatic assessment that combines all your income and calculates tax using the standard progressive brackets. If your secondary tax code caused you to overpay during the year, you will receive a refund. If you underpaid, you will have a small amount to pay. The secondary tax system exists to collect tax as close to the correct amount as possible throughout the year, so there are no surprises.

Using the wrong secondary tax code means you will either overpay or underpay tax during the year. If your code is too high (for example, using ST when you should use S), more tax will be deducted from each pay, but you will receive a refund after your end-of-year assessment. If your code is too low (for example, using SB when you should use SH), less tax will be deducted and you will likely owe money to IRD at the end of the year. IRD monitors tax codes through payday filing data and will notify you and your employer if they detect an unsuitable code. You can update your code at any time by giving your employer a new IR330 form.

Each employer deducts the ACC earner's levy independently from the income they pay you. They have no way of knowing what your other employer is deducting. For the 2026-2027 tax year, the ACC levy is 1.75% of your gross earnings, capped at $156,641 of total liable earnings across all jobs. If your combined income from all jobs exceeds this cap, you will overpay ACC during the year. ACC will perform a Multiple Employer Adjustment after the tax year ends and refund any excess levy you have paid. This calculator shows the ACC deduction your second employer will take from your pay — which is what you will actually see on your payslip.

Yes, both apply. KiwiSaver contributions are deducted by each employer on the income they pay you. Your second employer will deduct KiwiSaver at your chosen rate just like your first employer does. For student loans, the repayment threshold of $24,128 per year applies to your total income across all jobs. If your main job already exceeds this threshold, your second employer will deduct 12% student loan repayments from every dollar of your secondary income. If your main job is below the threshold, only the portion of your combined income above $24,128 will be subject to repayments. Make sure to include 'SL' in your secondary tax code so your employer makes the correct deductions.