Tax-Free Threshold Explained: What Happens If You Have Multiple Jobs

The tax-free threshold is one of the most valuable tax benefits for Australian workers, allowing you to earn up to $18,200 per year without paying income tax. But when you have multiple jobs, this benefit becomes more complicated. Many Australians with second or third jobs end up with unexpected tax bills because they don't understand how the threshold works across multiple employers. This guide explains exactly what you need to know.

What is the Tax-Free Threshold?

The tax-free threshold is the amount of income you can earn each financial year before you start paying income tax. For the 2025-26 financial year, this amount is $18,200. On every dollar above this threshold, you pay tax according to the progressive tax brackets.

When you complete a Tax File Number declaration for a new employer, you're asked whether you want to claim the tax-free threshold. If you answer yes, your employer calculates your tax withholding assuming you earn nothing from other sources. The first $18,200 of your annual income with that employer has no tax withheld.

This works perfectly for employees with a single job. But when you add a second employer also applying the tax-free threshold, problems emerge.

The Problem with Multiple Employers

Each employer calculates your tax withholding independently, based only on what they pay you. They don't know about your other income. If you claim the tax-free threshold from multiple employers, each one treats your income as if it's your only source of earnings.

Consider this scenario: You have two part-time jobs, each paying $25,000 per year. If you claim the tax-free threshold from both employers, each withholds tax assuming you earn only $25,000 annually. They'll withhold approximately $1,088 each based on the tax rates for a $25,000 income.

But your actual total income is $50,000, and your true tax liability is approximately $5,092. With only $2,176 withheld across both jobs, you'll face a $2,916 tax debt when you lodge your return. This unwelcome surprise catches many multi-job workers off guard.

The Correct Approach for Multiple Jobs

To avoid tax debts, you should claim the tax-free threshold from only one employer, typically your main job where you earn the most. For all other employers, select "No" when asked about the tax-free threshold on your TFN declaration.

When you don't claim the threshold, your second employer withholds tax at higher rates, assuming you've already used your threshold elsewhere. While this means less take-home pay from your secondary job, it better reflects your true tax situation.

This approach prevents under-withholding and the resulting tax debt. In fact, it often results in over-withholding, giving you a refund at tax time rather than a bill.

Calculating Your Combined Tax

Your total tax is calculated on your combined income from all sources, not separately for each job. Using the 2025-26 tax rates, someone earning $50,000 total from two jobs pays the same tax as someone earning $50,000 from a single job.

What differs is how the tax is collected throughout the year. With correct withholding (threshold claimed from one job only), the amount withheld across both jobs approximates your actual liability. With incorrect withholding (threshold claimed from both), not enough is collected, creating a year-end debt.

Use our pay calculator with the "No tax-free threshold" option to see how your secondary job income is taxed.

Real-World Examples

Let's work through some specific scenarios to illustrate the impact.

Sarah works full-time earning $70,000 and picks up casual weekend shifts earning $15,000. If she claims the threshold from her main job only, her tax position works out correctly. Her main job withholds approximately $12,367 (based on $70,000), and her casual job withholds approximately $4,800 (based on $15,000 without threshold). Total withheld is $17,167, which closely matches her actual liability on $85,000.

If Sarah mistakenly claims the threshold from both jobs, her main job withholds $12,367 and her casual job withholds only about $3,600 (treating $15,000 as her only income). She'll owe approximately $1,200 at tax time.

Low Income from Second Job

Some workers wonder if they need to worry about this when their second job income is small. The answer depends on your total income from all sources.

If your combined income stays below $18,200, you can claim the threshold from multiple employers without issue since you'd owe no tax anyway. However, this situation is rare for workers with multiple jobs.

More commonly, even a small secondary income pushes your total above the threshold. The tax on that additional income at your marginal rate won't be withheld if you've claimed the threshold from the second employer, creating a proportional tax debt.

Changing Jobs During the Year

If you change jobs and claim the threshold from each consecutive employer, you're likely to under-withhold. Each new employer treats you as if you're starting fresh, potentially applying the full tax-free benefit twice in one financial year.

The ATO looks at your total annual income, not when you earned it. Two jobs held sequentially can create the same issues as two jobs held simultaneously if the threshold is claimed from both.

When starting a new job, consider whether claiming the threshold makes sense given your year-to-date earnings. Sometimes choosing not to claim it from a new job that starts mid-year ensures adequate withholding.

Correcting Your Withholding

If you've been claiming the threshold from multiple employers, you can submit a new TFN declaration to your secondary employers to correct this. Inform them you want to stop claiming the threshold, and they'll adjust your withholding going forward.

This won't fix under-withholding from earlier in the year, but it prevents the problem from growing. You can also make voluntary additional payments to the ATO throughout the year if you want to avoid a year-end debt.

Some workers prefer to save the difference themselves, setting aside extra each pay period to cover their anticipated tax bill. This requires discipline but allows you to earn interest on the money until it's due.

Voluntary Tax Payments

The ATO allows voluntary PAYG installments if you regularly have tax debts from multiple income sources. You can set up a payment arrangement through myGov to pay estimated tax quarterly, spreading the burden and avoiding a single large payment.

This is particularly useful for those with regular side income from multiple sources where precise withholding is difficult to achieve.

Avoiding Unexpected Tax Bills

The simplest strategy for multiple-job workers is defensive. Always claim the threshold from your highest-paying job only. Accept that your take-home pay from secondary jobs will be lower due to higher withholding rates. View this as forced saving rather than lost income since you'd owe the money anyway.

Use tax calculators and the ATO's online resources to estimate your annual liability. Compare this to your expected total withholding. If there's a shortfall, either adjust your TFN declarations or set money aside.

Conclusion

The tax-free threshold is a valuable benefit, but it's designed for a single income source. When you have multiple jobs, understanding how to manage your TFN declarations prevents the common trap of under-withholding and unexpected tax debts.

Claim the threshold once only, from your main employer. Let your secondary employers withhold at the no-threshold rates. While your take-home pay from second jobs will be lower, this accurately reflects your true tax position and ensures you won't owe money at tax time.