How much tax do I pay on a second job?

Every dollar of your second job is taxed at your marginal rate from the first dollar, because the $18,200 tax-free threshold is already used up by your main job. So if your combined income sits in the 30% bracket, your second job is effectively taxed at about 32% (including the 2% Medicare levy). It is not an extra penalty — your total tax is the same as earning the combined amount in one job.

Should I claim the tax-free threshold on my second job?

Generally no. You claim the tax-free threshold from only one payer — usually your main or highest-paying job. If you claim it on both, not enough tax is withheld across the year and you'll likely get a bill at tax time. Tick 'No' to the tax-free threshold question on your second job's TFN declaration.

Why did I get a tax bill from my second job?

Usually because not enough tax was withheld — often from claiming the tax-free threshold on both jobs, or because the combined income pushed you into a higher bracket than either employer withheld for. The fix is to claim the threshold on only one job, and you can ask an employer to withhold extra to avoid a bill.

Second Job Tax Calculator

Work out the extra tax a second job adds and what you'll actually take home. It also explains why a second job feels taxed so much more heavily.

Last verified: 5 May 2026

Why is my second job taxed so much?

Because the $18,200 tax-free threshold is already used by your main job, every dollar of the second job is taxed at your marginal rate from dollar one. It feels brutal, but it's not a penalty — your total tax is the same as earning the lot in one job. Source: ATO.

Worked example. $75,000 main + $15,000 second: the second job adds about $4,950 in tax (≈33% effective, incl. Medicare), so you keep roughly $10,050 of the $15,000. Claim the tax-free threshold on only one job to avoid a bill.

General information and estimates only — not financial, tax, or legal advice. Always verify with a licensed adviser or the ATO.

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Why is my second job taxed so much?

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