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Secondary Tax Calculator

Calculate the correct tax code and deductions for your second job. Choose the right secondary tax code to avoid a bill at the end of the year.

By Konstantin IakovlevPublished 28 March 2026Last reviewed
Updated 2026-27 FYData stays on your deviceIRD sourced data

About this calculator

This calculator implements secondary tax codes (S, SH, ST, SA, SB) from Inland Revenue (IRD). Last consulted 1 April 2026. Verify the figures yourself by following the link.

Current NZ secondary tax codes

FY 2026-27 (matches income tax brackets)
  • •Code SB: 10.5% (total income ≤ $14k)
  • •Code S: 17.5% ($14k – $48k)
  • •Code SH: 30% ($48k – $70k)
  • •Code ST: 33% ($70k – $180k)
  • •Code SA: 39% (above $180k)
  • •No IRD number penalty: 45%

Source: IRD — Secondary tax codes

Disclaimer

This calculator provides estimates for general information purposes only. Results should not be relied upon as professional financial, tax, or legal advice. Tax rates and thresholds are based on publicly available IRD data and may change. Always consult a qualified tax agent or financial adviser for advice specific to your circumstances.

How NZ secondary tax codes work

Secondary tax codes (SB, S, SH, ST, SA) apply to a second job. The code is chosen based on your TOTAL income from all jobs, so the second employer withholds the right marginal rate.

  1. 1

    Add up total annual income from all sources

    Total = primary_income + secondary_income + other_income

    Includes every source: salary, contract work, dividends, rental, etc.

  2. 2

    Pick the matching secondary tax code

    SB ≤$14k · S $14-48k · SH $48-70k · ST $70-180k · SA >$180k

    Code reflects your top marginal bracket — secondary income is taxed entirely at this rate.

  3. 3

    Tax is deducted at the full bracket rate

    Secondary tax = secondary_income × bracket_rate (10.5% / 17.5% / 30% / 33% / 39%)

    Unlike primary income, NO progressive splitting — every dollar of secondary income hits one flat rate.

Worked example

Inputs: Primary $60k + Secondary $20k = $80k total income

Result: $80k falls in $70-180k → code ST → Secondary tax = $20,000 × 33% = $6,600/yr (~$127/week).

Frequently Asked Questions

What tax code should I use for my second job in NZ?
In New Zealand, if you have more than one source of income, you must use a secondary tax code for your additional income sources to avoid under-paying tax. For your main job (highest income), use the M tax code. For secondary jobs, the code depends on your estimated total combined income for the year: use S if your combined income will be between $48,001 and $70,000; SH if between $14,001 and $48,000; ST if between $70,001 and $180,000; and SA if over $180,000. If your secondary income is very low (under $14,000 when combined with other income), you can apply to IRD for a special tax code. Using the wrong code risks either underpaying (leading to a tax debt) or overpaying (leaving you out of pocket). You can update your tax code with your employer using an IR330 form. Source: IRD — Tax Codes (ird.govt.nz).
What is the difference between S, SH, ST and SA tax codes?
These are New Zealand's secondary income tax codes, each corresponding to a different combined income band. S (Secondary) applies when your total income from all sources is estimated between $48,001 and $70,000 — this attracts the 30% marginal tax rate. SH (Secondary Higher) applies when combined income is between $14,001 and $48,000, attracting the 17.5% rate. ST (Secondary Top) applies when combined income is between $70,001 and $180,000, corresponding to the 33% rate. SA (Secondary Additional) applies when combined income exceeds $180,000, attracting the top 39% rate. The code tells your employer which flat rate to withhold from that specific income stream. If your combined income crosses a threshold during the year, your year-end tax assessment via IRD's auto-calc will true up any underpayment or overpayment. Source: IRD — Secondary Tax Codes (ird.govt.nz).
Will I get a tax refund if I overpay on secondary tax?
Yes. If tō much tax has been withheld from your secondary income during the year, you are entitled to a refund. Each year after 31 March, Inland Revenue automatically runs a personal tax summary (auto-calc) for most wage and salary earners. If you have overpaid, IRD will issue a refund — typically by direct credit to your bank account within a few weeks of the assessment. To ensure you receive this, make sure your bank account details are up to date with IRD via myIR. Common reasons for overpayment include using a secondary tax code that was tō high for your actual combined income, or having varied income through the year. If you have not received a refund but believe you have overpaid, you can request a personal tax summary manually through myIR. Source: IRD — Tax Refunds (ird.govt.nz).
Does secondary tax apply to casual work?
Yes, secondary tax applies to casual work in New Zealand if you have another primary source of income. If casual work is your only source of income, you would use the M tax code (or M SL if you have a student loan). However, if you already have a main job and pick up casual work on the side, you must use the appropriate secondary tax code (S, SH, ST, or SA) depending on your estimated total combined income. Casual workers are employees for PAYE purposes and their employers must deduct tax correctly. This includes seasonal work, hospitality shifts, event staffing, and similar irregular work. If you are a genuinely self-employed contractor (receiving schedular payments), different tax rules apply and you may use a schedular payment tax rate instead. Source: IRD — Casual and Seasonal Workers (ird.govt.nz).

When you have two or more income sources in New Zealand, your secondary employment income is taxed at a flat rate based on the expected annual total of that secondary income. This prevents under-withholding that would result in a tax bill at year end.

How this calculator works

Secondary tax codes (SH, SB, S, ST, SA) each correspond to a flat rate that matches a single NZ tax bracket. You choose the code that reflects the bracket your secondary income falls into for the year. Unlike primary income under tax code M, no graduated calculation is used — the flat rate applies to every dollar of secondary pay. You may still receive a refund or owe a small amount at year end if total income across all jobs lands in a different bracket.

Secondary Tax Codes and Rates 2026-27

SH — up to $14,000/year10.5%
SB — $14,001 to $48,000/year17.5%
S — $48,001 to $70,000/year30%
ST — $70,001 to $180,000/year33%
SA — $180,001+/year39%

The code is based on the expected total of the secondary income source for the year, not combined income. If unsure, choose the code that matches the most likely annual total from that job.

ACC Earner's Levy on Secondary Income

Rate$1.75 per $100 of liable earnings
Applies toAll liable earnings across all jobs combined up to $156,641
If already capped at main jobNo further levy deducted at secondary job

Worked Examples

Main job $60,000/year + secondary job earning $15,000/year

Secondary income taxed at SB rate (17.5%). Annual secondary tax deducted: $2,625.

  1. Secondary annual income: $15,000
  2. This falls in the $14,001–$48,000 bracket → use tax code SB (17.5%)
  3. Annual secondary PAYE = $15,000 × 17.5% = $2,625
  4. Weekly secondary PAYE = $2,625 / 52 = $50.48
  5. Note: main job is already taxed progressively on $60,000; combined income $75,000 means a small refund or bill may arise at year end

Main job $80,000/year + secondary job earning $30,000/year

Secondary income taxed at SB rate (17.5%). Annual secondary tax deducted: $5,250.

  1. Secondary annual income: $30,000
  2. This falls in the $14,001–$48,000 bracket → use tax code SB (17.5%)
  3. Annual secondary PAYE = $30,000 × 17.5% = $5,250
  4. Weekly secondary PAYE = $5,250 / 52 = $100.96
  5. Combined income $110,000 means the top $40,000 of secondary income is actually in the 33% bracket
  6. A top-up payment to IRD may be required at year end; consider using tax code S or ST instead to over-withhold slightly

Built and maintained by Konstantin Iakovlev. Data sourced from the IRD and official New Zealand government sources.

Last reviewed:

Official Sources

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