Taking on a second job is one of the fastest ways to lift your income — and one of the most common causes of a surprise tax bill. The confusion usually starts with the first payslip from the second job, which looks heavily taxed compared with your main job. There is actually no special “second job tax rate” in Australia. What you are seeing is the tax-free threshold at work, and understanding it is the difference between a refund and a debt at tax time.
To model your combined income and tax, use the income tax calculator or the net to gross calculator.
There is no separate second-job tax rate
Australia taxes your total taxable income from all sources at the same progressive resident rates. For 2025–26, those rates are: 0% up to $18,200, 16% from $18,201 to $45,000, 30% from $45,001 to $135,000, 37% from $135,001 to $190,000, and 45% above $190,000. (From 1 July 2026, the 16% rate drops to 15% for the 2026–27 year.) Whether your income comes from one employer, two employers or a side business, the final tax bill depends only on the combined total.
What differs between jobs is withholding — the tax your employer deducts from each pay and sends to the ATO on your behalf. Withholding is an estimate, credited against your final tax bill when you lodge your return. If too much was withheld across all jobs, you get a refund. If too little, you owe the difference.
The tax-free threshold: claim it once
Australian residents for tax purposes can earn the first $18,200 of annual income tax-free. You claim the threshold on the Tax File Number (TFN) declaration you give each employer when you start a job. The critical rule: claim it from only one employer at a time — normally your main or highest-paying job.
Your main employer then withholds tax as if your first $18,200 is tax-free. Your second employer, where you answer “No” to claiming the threshold, withholds tax from the first dollar they pay you, at the marginal rates. That is why the second payslip looks harsh: tax is being deducted from dollar one, while your main job’s payslip shows no tax on the first chunk of pay.
The one exception: if you are certain your total income from all payers for the year will be $18,200 or less, the ATO allows you to claim the threshold from more than one payer. If your income later rises above $18,200, update one employer immediately so you stop claiming it twice.
Worked example: $60,000 main job plus $25,000 second job
Take someone earning $60,000 in their main job and $25,000 in a second job — $85,000 combined. Their final tax position for 2025–26 is calculated on the total:
| Income slice | Rate | Tax |
|---|---|---|
| $0 – $18,200 | 0% | $0 |
| $18,201 – $45,000 | 16% | $4,288 |
| $45,001 – $85,000 | 30% | $12,000 |
| Total income tax | $16,288 | |
| Medicare levy (2% of $85,000) | $1,700 | |
| Total tax and Medicare | $17,988 | |
| Take-home pay | $67,012 |
Withholding should roughly track this if the setup is right: the main employer withholds against the $60,000 with the threshold applied, and the second employer withholds from the first dollar. When the return is lodged, the withheld amounts are credited and any small difference is refunded or billed.
The double-claim trap
The expensive mistake is claiming the threshold from both employers. In that case, both payroll systems treat the first $18,200 from each job as tax-free — so $36,400 escapes withholding instead of $18,200. On our example, that under-withholds roughly $2,912 of income tax (16% of the extra $18,200) plus the Medicare levy on the combined income, which is assessed at tax time rather than withheld. The result is a tax bill that can easily reach several thousand dollars, and it is one of the most common reasons second-job workers owe money at tax time.
The fix is simple: give the second employer (or the lower-paying one) a new TFN declaration answering “No” to the threshold question. You can also lodge a withholding declaration to ask an employer to withhold extra tax voluntarily — useful if you have a HECS-HELP debt or expect to owe the Medicare levy surcharge, both of which are calculated on your total income and are not covered by ordinary withholding.
How withholding is actually calculated on the second job
Employers do not guess your withholding — they use the ATO’s PAYG withholding tax tables. For an employee who has claimed the threshold, the weekly tax table builds the $18,200 tax-free amount into the calculation, so no tax is withheld until weekly pay passes roughly $350. For an employee who has not claimed the threshold, a separate no-threshold table applies, and tax is withheld from the first dollar at the marginal rates, starting at 16% in 2025–26 (15% from 1 July 2026).
This is also why the second job’s withholding rarely matches the final bill exactly. Each employer withholds as if their job were your only income at that pay level, but your final rate depends on the combined total. If your main job already puts you into the 30% bracket, the second job’s income is effectively taxed at 30% (plus Medicare and any HECS repayment) in the final assessment, even though withholding on it started at 16%. That gap is the most common reason second-job workers end the year owing money despite having tax withheld from every pay. A withholding declaration asking the second employer to deduct an extra amount each pay is the simplest way to close it during the year rather than at tax time.
One more scenario worth knowing: if your second job is contract work under an ABN rather than employment, there is no employer withholding at all (unless you fail to quote an ABN, in which case the payer must withhold 47%). You instead set money aside yourself and pay it through quarterly PAYG instalments or at tax time. The same progressive rates apply, but the cash-flow discipline is entirely yours — a common trap for first-time side hustlers.
Second jobs, HECS and super
- HECS-HELP: compulsory repayments are calculated on your total repayment income. A second job can push you over the $67,000 threshold (2025–26) even if neither job alone does. If no extra withholding is arranged, the repayment lands as a tax bill.
- Medicare levy surcharge: surcharge liability is assessed on combined family income. Two jobs can push a single person over the surcharge threshold even when each job alone would not.
- Superannuation: each employer must pay the 12% super guarantee on your ordinary time earnings from that job, separately. There is no combining across employers for SG purposes, and each employer applies the quarterly maximum super contribution base independently.
- Leave and entitlements: entitlements are per job. A part-time second job accrues leave on its own hours; a casual second job attracts casual loading instead.
Getting the setup right
- Claim the tax-free threshold from your highest-paying or most stable job only.
- Answer “No” to the threshold question on every other TFN declaration.
- If you have a HECS debt, consider a withholding declaration for extra tax on your second job so the repayment is covered during the year.
- Use the ATO’s tax withheld calculator mid-year to check whether your combined withholding tracks your expected final bill.
- Keep every payment summary and income statement — your tax return must include income from all jobs, and the ATO pre-fills most of it from employer reports.
Frequently asked questions
Is there a higher tax rate for a second job in Australia?
No. Your final tax is calculated on your combined income at the normal progressive rates. The higher withholding on a second payslip is because the tax-free threshold is not applied there, not because of a special rate.
Should I claim the tax-free threshold from my second job?
Generally no, if your combined income will exceed $18,200. Claim it from your main job only. The exception is when you are certain your total income from all payers will be $18,200 or less for the year.
Why is my second job taxed so much?
Because tax is withheld from the first dollar, without the $18,200 tax-free portion. It is withholding, not extra tax: it is credited against your final bill, and any excess comes back as a refund.
What happens if I claimed the threshold from both jobs?
You will likely owe tax when you lodge your return — roughly $2,912 plus Medicare effects on an $18,200 double-claim at the 16% rate. Fix it now with a new TFN declaration to one employer, and consider a withholding declaration for extra tax to cover the shortfall.
Do I need to lodge a tax return if I have two jobs?
Yes, in almost all cases. With combined income above $18,200 you must lodge, and lodging is how the ATO reconciles withholding from all your employers into one final assessment.
Does my second employer know about my first job?
Your employer does not see your other income. The TFN declaration only asks whether you claim the threshold from them. It is your responsibility to claim it from one payer only.
Conclusion
A second job is taxed exactly like a first job — on your total income, at the normal rates. The payslip shock comes from withholding, and the tax bill comes from claiming the $18,200 threshold twice. Set it up correctly — threshold from one employer, extra withholding if you have HECS or surcharge exposure — and the second job delivers what it should: extra income without an end-of-year surprise. Run your combined income through the income tax calculator before the financial year ends so there are no surprises in July.