A bonus rarely lands in your bank account at the full amount quoted, and the gap often looks larger than expected. This calculator shows the estimated tax on a one-off bonus, commission or lump sum payment, and the net bonus you keep, based on your regular salary for the same financial year. Enter your salary and the bonus amount, choose whether to include the Medicare levy, and you get the difference in plain figures rather than a guess from a single payslip. It suits employees checking an end of year bonus, sales staff estimating commission, and anyone offered a lump sum who wants to plan around the after-tax amount before the money arrives. Everything runs in your browser on this device. Nothing you type is uploaded, sent to a server or stored, so your salary and bonus details stay private while you test different amounts.
How it works
You enter three things: your annual salary before the bonus, the gross bonus amount, and the financial year the bonus will be paid in. You can also choose whether the estimate includes the Medicare levy. That choice matters because the levy is 2 percent of taxable income for most people, and it applies to the bonus as part of your total income for the year.
The method is the marginal method, explained step by step. First, the calculator works out your total annual deductions on salary alone, meaning income tax under the Australian resident rates plus the Medicare levy if you included it. Next, it does the same calculation on salary plus bonus. The difference between those two totals is the estimated tax on the bonus itself. Your net bonus is the gross bonus minus that difference.
This is deliberately different from taxing the bonus on its own. In Australia a bonus is not taxed at a special bonus rate. It is ordinary income, added to your salary and taxed through the same resident brackets that apply to everyone. For 2025-26 those brackets start with no tax on the first $18,200, then 16 cents per dollar over $18,200 up to $45,000, then $4,288 plus 30 cents per dollar over $45,000 up to $135,000, with higher brackets above that. Because the bonus sits on top of your salary, it is usually taxed at your highest marginal rate, and part of it can cross into the next bracket if the amount is large enough.
The financial year selector matters for the same reason. Resident rates change between years. The second bracket is 16 percent in 2025-26, then falls to a legislated 15 percent in 2026-27 and 14 percent in 2027-28, with thresholds otherwise unchanged. Pick the year the bonus will actually be paid, not the year you earned it, if the two differ around 30 June.
One limit needs to be clear. This is an estimated withholding figure using the annualised marginal method described above. It is not a payroll calculation using the ATO tax tables or the ATO statement of formulas, and your employer may withhold a different amount in the actual pay run. Payroll often withholds more from a single pay because the bonus is treated as if that higher pay level will continue. Any over-withholding is sorted out when you lodge your tax return and your real tax is worked out on your total income for the year.
The result is most useful for planning: comparing two bonus offers, deciding how much to set aside, or checking whether a surprisingly small net payment is broadly in line with your marginal rate before you query payroll.
Worked example
Take a salary of $80,000 and a bonus of $10,000 in 2025-26, with the Medicare levy included.
| Item | Amount |
|---|---|
| Income tax on the $80,000 salary alone | $14,788 |
| Medicare levy on $80,000 at 2 percent | $1,600 |
| Total deductions on salary alone | $16,388 |
| Income tax on $90,000, salary plus bonus | $17,788 |
| Medicare levy on $90,000 at 2 percent | $1,800 |
| Total deductions on salary plus bonus | $19,588 |
| Tax on the bonus, the difference | $3,200 |
| Net bonus, $10,000 – $3,200 | $6,800 |
In this example the whole bonus sits in the same bracket, taxed at 30 cents in the dollar plus the 2 percent levy, which is why the combined effect is $3,200 on a $10,000 payment. A larger bonus, or a salary closer to the next threshold at $135,000, could see part of the amount taxed at a higher rate.
Common questions
Why does my bonus look so heavily taxed?
In the pay run, payroll treats the bonus as if you will earn that extra amount every pay, which pushes the withholding up for that one pay. Over the full year the bonus is taxed at your marginal rate like any other income. If too much was withheld, the difference comes back in your tax return.
How does this calculator work out the tax on a bonus?
It uses the marginal method: it works out the annual tax on your salary, then the annual tax on your salary plus the bonus, and the difference is the estimated tax on the bonus itself. This mirrors the way the ATO lump sum method spreads a bonus across the year instead of taxing it all in one pay period.
Is a commission taxed the same way as a bonus?
Yes. Commissions, bonuses and most lump sum payments are ordinary income. They are taxed at your marginal rates for the year, and withholding on them follows the same lump sum approach.
Does super get paid on a bonus?
Usually yes, if the bonus relates to your ordinary hours of work, because bonuses are generally ordinary time earnings for super guarantee purposes. A bonus for work outside ordinary hours may be treated differently. Your payslip and fund statements show what was paid.
Will I get a refund for the extra tax withheld on my bonus?
Often, yes. Withholding is only an estimate collected during the year. When you lodge your tax return, your actual tax is calculated on your total income for the year, and any over-withholding is refunded.
Before you rely on this estimate
This calculator gives general information and an estimate only, based on the published ATO resident rates for the year you select. It is not financial, tax or legal advice, and it does not cover tax offsets, HELP debts or your personal circumstances. Read our Disclaimer before relying on any figure, and talk to a registered tax agent for advice on your own situation. To check the wider picture, try the Salary Calculator for your regular take-home pay, the Pay Calculator for a full payslip style breakdown, or the PAYG Calculator to estimate withholding from a single pay.