Tax Code Calculator New Zealand 2025/26
Find your correct IRD tax code (M, ME, S, SH, ST, SA, SB), understand secondary tax withholding, and see how to fix a wrong code. Secondary tax is NOT extra tax — it's higher withholding with a year-end square-up.
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How to Use This Calculator
Tab "Find My Code"
Answer two questions: is this your main job, and what is your expected annual income? For your main job, the calculator recommends M or ME (if IETC-eligible). For a secondary job, enter your total combined income from all jobs — the calculator recommends the correct secondary code (S, SH, ST, SA, or SB). Once you know your code, submit an IR330 form to your employer.
Tab "Code Impact"
Enter your main job income, secondary job income, and the secondary code currently on your payroll. The calculator shows how much tax is being withheld, what the correct withholding should be, and whether you are on track for a refund or an end-of-year bill. Use this to decide whether to change your secondary tax code.
Tab "Fix Wrong Code"
Select the wrong code that is currently being applied, the correct code you should be using, and the income already earned under the wrong code. The calculator estimates the overpayment or underpayment and explains the steps to fix it — including submitting a new IR330 form and, where relevant, contacting IRD about an interim return.
NZ Tax Code Reference Table 2025/26
| Code | When to use | Withholding rate | Total income range |
|---|---|---|---|
| M | Main or only job (standard) | Progressive PAYE | Any income |
| ME | Main job + IETC eligible | Progressive PAYE – IETC | $24,000–$48,000 (no govt benefits) |
| S | Secondary job — low total income | 10.5% | Total $0–$15,600 |
| SH | Secondary job — mid total income | 17.5% | Total $15,601–$53,500 |
| ST | Secondary job — upper-mid total income | 30% | Total $53,501–$78,100 |
| SA | Secondary job — high total income | 33% | Total $78,101–$180,000 |
| SB | Secondary job — very high total income | 39% | Total $180,001+ |
| No code | No IR330 provided — avoid this | 45% | Any income |
| WT | Schedular (contract) payments | As specified | Contractors only |
| CAE | Casual agricultural employees | Flat rate | Seasonal ag work |
Total income = your income from all jobs combined. Your secondary employer withholds at a flat rate matching your total income bracket. The M/ME code uses progressive PAYE tables — IRD provides these to employers.
How Secondary Tax Actually Works
Why higher withholding?
Your total income determines your tax bracket. Your secondary employer does not know about your main job income, so if they withheld at the lowest rate (10.5%), you would underpay throughout the year.
Secondary codes (S, SH, ST, SA, SB) apply a flat rate that matches the marginal tax bracket your total income falls into, so the right amount is withheld week by week.
Year-end square-up:
After 31 March, IRD calculates your total tax across ALL income. Overpaid → refund. Underpaid → bill.
NZ income tax brackets 2025/26:
10.5% on $0–$15,600
17.5% on $15,601–$53,500
30% on $53,501–$78,100
33% on $78,101–$180,000
39% on $180,001+
Example — Main Job $55,000 + Weekend Job $12,000
Scenario: Full-time nurse ($55K) with weekend café work ($12K)
Sarah works full-time as a nurse earning $55,000 (main job, code M) and picks up weekend shifts at a café earning $12,000 per year. Her total income is $67,000.
Sarah's café employer withholds $3,600 over the year using code ST. The nurse employer withholds PAYE on $55,000 using code M. At year end, IRD reconciles the total. If Sarah had used code S (10.5%) on her café job, only $1,260 would be withheld — leaving her with an end-of-year bill of approximately $2,340 instead of a refund.
Key takeaway: Using the right secondary code means no surprise bill in April. Secondary tax is simply spreading your true annual tax liability across your pay periods.