Site Allowance Tax Impact Calculator
See roughly how much tax comes out of a taxable site allowance and what you keep. Enter your annual allowance and your marginal tax rate, and this calculator estimates the tax payable and the net after-tax amount.
Enter Values
Minimum 0
Minimum 0
Minimum 0
Before you rely on this: First-pass guide only. Verify safety-critical or regulated work against the relevant standards, your project requirements and a qualified professional.
How to use this calculator
- Enter your annual site allowance in dollars (for example the yearly total from the Site Allowance Calculator).
- Enter your marginal tax rate as a percentage (for example 37 for the 37% bracket).
- Optionally enter your swings per year to also see the net allowance in-hand per swing.
How it works
The estimate applies your marginal rate to the whole allowance: tax on allowance = annual allowance × marginal rate ÷ 100. The net after-tax allowance is the gross allowance minus that tax. If you supply swings per year, the net is divided by that number to show the after-tax allowance you keep per swing.
Worked example
Worked example. A $31,200 annual allowance taxed at a 37% marginal rate. Tax = $31,200 × 0.37 = $11,544.00, leaving a net after-tax allowance of $31,200 − $11,544 = $19,656.00. Spread over 26 swings, that is $19,656 ÷ 26 = $756.00 in hand per swing.
Common mistakes
- Treating this as your exact tax bill. It uses one flat marginal rate, not the progressive brackets, Medicare levy or offsets, so real tax differs.
- Taxing an allowance that is actually tax-free. Genuine LAFHA benefits may be exempt or concessionally taxed — don't assume the full marginal rate applies.
- Using the wrong marginal rate. Your marginal rate depends on your total taxable income, not just the allowance in isolation.
Frequently asked questions
Which marginal tax rate should I use?
Use the rate that applies to your top slice of income for the year — for many FIFO workers that is 32.5%, 37% or 45% before the Medicare levy. Check the current ATO income tax rates or ask your tax agent.
Is this a real tax calculation?
No. It is a rough single-rate estimate and is not tax advice. Your actual tax depends on total income, the progressive brackets, the Medicare levy, offsets and deductions, and some allowances are tax-free. Confirm with a registered tax agent or the ATO.
Related tools
- Site Allowance Calculator
- Salary vs Day Rate Comparison Calculator
- Hourly Rate to Annual FIFO Salary Calculator
- FIFO Roster Calculator
- Swings Until Savings Goal Calculator
- Age Calculator
Explore more in Time, Date, Roster & FIFO.
Cite this tool
Zerdly. (2026). Site Allowance Tax Impact Calculator. Retrieved from https://www.zerdly.com/tools/site-allowance-tax-impact-calculator/
Tip: Enter any known values to calculate the remaining results.
Designed to run locally in your browser. Tool inputs are not intentionally stored by Zerdly unless stated otherwise.