Second Job Tax Calculator Australia: How Much Tax Do You Pay on a Second Income?

Published 3 March 2026 · 6 min read

Picking up a second job is a great way to boost your income — but it comes with a tax sting that surprises a lot of Australians. Unlike your main job, your second employer withholds tax at a much higher rate from day one. This guide explains exactly why that happens, how much extra tax you'll pay in FY 2025-26, and what you can do to minimise a nasty tax bill at year-end.

Why Is Your Second Job Taxed at a Higher Rate?

Australia uses a progressive tax system — the more you earn, the higher the rate applied to each extra dollar. Your tax-free threshold ($18,200) and low-income offsets can only be claimed once, against your primary job.

When you start a second job, you fill out a Tax File Number (TFN) declaration and tick "No" to claiming the tax-free threshold. This tells your second employer to withhold tax starting at the lowest applicable marginal rate for all income — no free threshold, no offsets. In practice, that means:

• Every dollar from your second job is stacked on top of your first job income
• Those dollars are taxed at whatever marginal rate applies to that combined income level
• Your second employer withholds at the 32.5% "no-threshold" rate as a default (this covers tax + Medicare levy), unless your income means a higher rate applies

The result: your second job appears heavily taxed. But it's not unfair — it reflects the fact that those extra dollars genuinely are taxed at a higher rate once your main income has already used up the lower brackets.

FY 2025-26 Tax Brackets: Where Your Second Income Falls

Here are the Australian income tax rates for FY 2025-26 (post Stage 3 Tax Cuts). Your second job income is taxed at the rate matching your combined income from both jobs:

If your main job pays $60,000, your second job income immediately falls in the 30% bracket — every dollar earned from that second job is taxed at 30% income tax plus 2% Medicare levy. Use our income tax calculator to see how the brackets apply to your combined income.

Second Job Tax Examples for FY 2025-26

Let's look at three realistic scenarios to see how much tax a second job actually costs you.

Example 1: Main job $55,000 + Second job $15,000

Example 2: Main job $80,000 + Second job $20,000

Example 3: Main job $120,000 + Second job $25,000

Notice that in Example 3, crossing the $135,000 bracket means part of that second job income is taxed at 37% + 2% Medicare = 39%. The higher your main job salary, the more aggressively the second job is taxed. Check your own combined figure using our take-home pay calculator.

Will I Get a Tax Bill or a Refund at the End of the Year?

This depends on how accurately each employer withholds tax throughout the year. There are two common scenarios:

Scenario A: You'll owe extra tax (tax bill)

If your second employer withholds at the standard "no-threshold" rate of 32.5% (which includes 2% Medicare), but your actual marginal rate on that income is higher — for example 39% or 47% — you'll have a tax shortfall at year-end. You'll owe the ATO the difference when you lodge your return.

Scenario B: You get a refund

If your combined income turns out to be lower than expected, or if your second employer over-withheld (some do withhold at higher rates to be safe), you may receive a refund. This is less common with second jobs — over-withholding is more typical at a primary job.

The safest approach is to ask your second employer to withhold at a higher rate if your combined income will push you into a higher bracket. You can request this in writing — there's no official ATO form required.

HECS-HELP Debt and Second Jobs

If you have a HECS-HELP student loan, your compulsory repayment is calculated on your total income from all sources — not just your main job. The FY 2025-26 repayment threshold is $67,000.

If your first job alone is below $67,000 but your combined income crosses that line, you'll owe HECS repayments at tax time that weren't withheld during the year. The repayment rates for FY 2025-26:

• $67,001 – $125,000: repay 15c for every dollar above $67,000
• $125,001 – $179,285: $8,700 + 17c for every dollar above $125,000
• $179,286+: 10% of total income

For example, if your combined income is $90,000 and you have HECS debt, your compulsory repayment is ($90,000 − $67,000) × 15% = $3,450. This is on top of your regular income tax. Use our HECS-HELP repayment calculator to work out your combined repayment obligation.

Medicare Levy Surcharge and Private Health Insurance

The Medicare Levy Surcharge (MLS) kicks in if your income exceeds $101,001 and you don't hold adequate private hospital cover. A second job that pushes you past this threshold could trigger an additional tax of 1% to 1.5% on your entire income.

• $101,001 – $118,000: 1.0% MLS
• $118,001 – $158,000: 1.25% MLS
• $158,001+: 1.5% MLS

If taking a second job pushes you above $101,001, compare the cost of private hospital insurance against the MLS you'd pay — often the insurance is cheaper. See our Medicare levy calculator for full details.

Superannuation on a Second Job

Your second employer must also pay Superannuation Guarantee (SGC) contributions on your wages at 12% in FY 2025-26 — provided you earn at least $450 per month from them (note: the $450/month threshold was actually abolished from 1 July 2022, so super is now payable regardless of monthly earnings).

Having two employers making super contributions could push you toward your concessional contributions cap of $30,000. If both employers contribute SGC and you also salary sacrifice, monitor your total closely. Exceeding the cap means the excess is taxed at your marginal rate rather than the concessional 15%.

Use our superannuation calculator to track contributions from multiple employers and check your cap headroom.

Tips to Manage Tax on a Second Job

• Ask your second employer to withhold extra tax. If you know your combined income will push you into a higher bracket, request a higher withholding rate in writing. This avoids a lump-sum bill at year-end.
• Never claim the tax-free threshold at both jobs. You can only claim it at one employer. Claiming it at both will guarantee a tax bill.
• Set aside a tax buffer. A simple rule of thumb: set aside 32–47% of each second-job pay cheque depending on your combined income bracket. Keep it in a separate savings account and use it to pay your tax bill at year-end.
• Consider salary sacrificing at your main job. Salary sacrificing into super reduces your taxable income, which can push your combined income into a lower bracket — reducing the marginal rate on your second job income. See our salary sacrifice calculator.
• Claim all allowable deductions. Work-related expenses for either job reduce your taxable income. Keep receipts throughout the year.
• Lodge your tax return promptly after 30 June. If you're owed a refund, earlier lodgement means faster payment. If you owe, knowing the amount early gives you more time to pay.

Summary: Second Job Tax in Australia

Key takeaways for FY 2025-26:

• Your second job income is taxed at your marginal rate based on combined income from all jobs
• You can only claim the tax-free threshold at one employer — your main job
• At a $60,000 main job, each dollar from a second job is taxed at 32% (30% tax + 2% Medicare)
• HECS repayments are based on total combined income — a second job can trigger or increase repayments
• Crossing $101,001 combined can trigger the Medicare Levy Surcharge
• Both employers must pay 12% super — watch your concessional cap ($30,000)
• Ask your second employer to withhold at a higher rate to avoid a year-end tax bill

The extra income from a second job is absolutely worth it in most cases — even after tax, you're taking home real money. The key is understanding what you'll actually keep so there are no surprises. Use our take-home pay calculator to model your combined salary, or our income tax calculator to see exactly how much of that second income goes to the ATO.