Second Job Tax Calculator AU 2025-26

What this calculator works out

If you have two jobs in Australia, you have probably noticed that the second job withholds a lot more tax per dollar than the first. That is not a separate "second job tax rate" — it is the PAYG withholding system doing the maths assuming you have already used the $18,200 tax-free threshold somewhere else.

This calculator runs both sides of that equation for FY 2025-26:

• Per-job withholding under the standard schedule (NAT 1004, with tax-free threshold) and the no-threshold schedule (NAT 3539);
• Year-end actual liability on combined income against the FY 2025-26 marginal brackets, plus 2% Medicare levy and any HECS-HELP repayment;
• Refund or shortfall projection so you know whether to plan for a tax bill in October or a refund in August.

It also recommends which job should claim the threshold (almost always the higher-paying one) and flags HECS-HELP shortfalls when neither job individually crosses the $67,000 repayment threshold but combined income does.

The formula and where the rates come from

// FY 2025-26 resident brackets (post-Stage-3 amended):
//   0 – 18,200          : 0%
//   18,201 – 45,000     : 16% on excess over 18,200
//   45,001 – 135,000    : $4,288 + 30% on excess over 45,000
//   135,001 – 190,000   : $31,288 + 37% on excess over 135,000
//   190,001+            : $51,638 + 45% on excess over 190,000

combinedIncome = job1Income + job2Income
incomeTax      = bracketTax(combinedIncome)
medicareLevy   = combinedIncome × 0.02
hecsRepayment  = if hasHECS && combinedIncome > 67,000 → graduated 1-10%
totalLiability = incomeTax + medicareLevy + hecsRepayment

// PAYG withholding (annualised approximation of NAT 1004 / NAT 3539):
withholdJob1 = tftcOnJob1 ? bracketTax(job1) + 2% × job1
                          : (bracketTax(job1 + 18,200) − bracketTax(18,200)) + 2% × job1
withholdJob2 = tftcOnJob2 ? bracketTax(job2) + 2% × job2
                          : (bracketTax(job2 + 18,200) − bracketTax(18,200)) + 2% × job2

refundOrShortfall = totalWithheld − totalLiability

The marginal brackets are published on the ATO individual income tax rates page. The PAYG schedules are published as tax tables (NAT 1004 with threshold, NAT 3539 without). The HECS-HELP thresholds are on the study and training loan repayment thresholds page and are indexed each financial year.

How to read the inputs

• Job 1 / Job 2 annual gross income — your expected annual gross from each role. For casual or variable-hour jobs, average a typical year.
• Claim tax-free threshold on — pick the job whose TFN declaration has "Yes" for Q9. This is the one whose payroll uses NAT 1004; the other job uses NAT 3539.
• HECS-HELP debt — tick if you have any FEE-HELP, HECS-HELP, VET Student Loan or similar Commonwealth study debt. Repayment is calculated on combined income.

Worked examples

1. $60k + $20k, threshold on job 1, no HECS. Job 1 withholds ~$9,988 (8,788 income tax + $1,200 Medicare). Job 2 withholds ~$3,600 ($3,200 + $400). Total withheld $13,588. Combined liability = $14,788 + $1,600 = $16,388. Shortfall ~$2,800 at year-end.

2. Same $60k + $20k, threshold on job 2 (wrong job), no HECS. Job 1 withholds more under NAT 3539 ($60k no-TFT ≈ $14,488). Job 2 withholds less under NAT 1004 ($20k = $208 + $400 ≈ $608). Total withheld $15,096 — closer to the $16,388 liability but the shortfall pattern is similar. The recommendation always favours the higher-paying job for the cleanest year-end.

3. $50k + $30k, threshold on job 1, with HECS. Combined $80,000 → HECS @ 3% = $2,400. Liability ~$14,788 + $1,600 + $2,400 = $18,788. Without extra HECS withholding from either employer, shortfall ~$3,000-$5,000. Solution: ask job 1's payroll to also withhold for HECS.

4. $40k + $30k, threshold on job 1, with HECS. Combined $70k crosses the HECS threshold ($67,000 in 2025-26). Each individual job is below the HECS threshold so neither employer withholds extra HECS — but at year-end you owe roughly 2% × $70,000 = $1,400 HECS. Always-flag scenario.

5. $80k + $0 (single job, used as control). No second-job effect. Total withheld and liability should match closely.

6. $90k + $40k, threshold on job 1, no HECS. Combined $130k pushes you well into the 30% bracket. Job 2 at NAT 3539 withholds at the 30% marginal rate from the first dollar — withholding usually slightly over-collects, giving a small refund.

7. $50k + $50k, threshold on job 1, with HECS. Combined $100k = HECS @ 5% = $5,000. Both jobs over $45k, so withholding is reasonably close. Verify with the calculator and consider asking the higher-paying job to add HECS withholding.

Common pitfalls

• There is no special "second job tax rate". The 30%-from-the-first-dollar feel is just NAT 3539 doing the maths assuming the threshold is used elsewhere.
• Always claim the threshold on your highest-paying job. Claiming it on a low-paid casual job leaves your main job under-withholding and creates a year-end bill.
• HECS-HELP is the most common silent shortfall. Both jobs withhold based on individual pay; HECS is calculated on combined income. Two part-time jobs can leave you with a $1,000-$3,000 HECS bill in October.
• Update your TFN declaration when a job ends. If your higher-paying job ends, switch the threshold to the remaining job by lodging a new TFN declaration.
• The Low Income Tax Offset (LITO) is automatic at year-end — up to $700 for incomes below $37,500, phasing out by $66,667. Not modelled here for simplicity but it can convert a small shortfall into a small refund.
• Salary sacrifice happens before this calculator's "income". Use your post-salary-sacrifice gross. Reportable fringe benefits add back for some tests (HECS, Medicare levy surcharge).
• Holiday pay and bonuses can throw off your withholding. Lump sums use a different schedule (Method B) and may over-withhold for the year.
• Foreign residents have no tax-free threshold and a different bracket. This calculator is for Australian residents for tax purposes.

Related calculators

• HECS-HELP Repayment Calculator (AU) — full repayment schedule on combined income.
• Working Holiday Tax Calculator (AU) — separate WHM rates (different from second-job).
• Medicare Levy Reduction Calculator (AU) — low-income reductions on the 2% levy.
• Work-from-Home Tax Deduction Calculator (AU) — deductions to reduce combined income.
• SAPTO & LITO Tax Offset Calculator (AU) — automatic offsets that change the year-end picture.

Sources:

• ATO — Multiple jobs or change of job (tax-free threshold)
• ATO — Tax tables (PAYG withholding)
• ATO — Tax Withheld Calculator
• ATO — Individual income tax rates (FY 2025-26)
• ATO — Study and training loan repayment thresholds and rates